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	Derivées partielle		1999-10-19
		Arnaud Flandin pose la question : Quel est la definition des derivées partielle Claude Tardif lui répond.
	Adding a service charge and the VAT		2020-04-30
		richard pose la question : was given a figure by a client been performance bonus of staff , the figure is 806,698.35 from this 806,698.35 is my company service charge of 10% and 5% of the service charge will be Vat to government in summary from 806,698.35 is 10% of service charge and 5% of service charge is the VAT Penny Nom lui répond.
	Price before VAT and a discount		2018-11-15
		Carol pose la question : I bought a computer for £330. The selling price included VAT at 20%. Then I was allowed a staff discount of £30. What was it’s original price before the VAT and staff discount? Penny Nom lui répond.
	Pre tax and post tax percentages		2018-05-22
		Tom pose la question : Hi, I work in a clothes shop which can also do mail-orders. My Head Office has sent a report with which we can check the records we keep in store tally with those at HO. According to that report we have taken £2578.25 in orders, excluding VAT (20%), which would therefore be £3093.91 including VAT (2578.25+20%=3093.91). According to my records, we have taken £3179.32 including VAT, which would be £2543.45 excluding VAT (3179.32-20%=2543.45). Why is it that the difference between the VAT inclusive figures (3179.32-3093.91) is +£85.41, but the difference between the VAT exclusive figures (2543.45-2578.26) is -£34.81? Now, I can see from the report that 1 order has not been recorded by HO, and I know that our average order value is around £30, so the -£34.81 makes sense. But surely both figures should be a minus, regardless of whether they include VAT? I'm sure there is an obvious answer, but I just cannot see it! Any help would be gratefully received. Thanks, Tom Penny Nom lui répond.
	More on the curvature of the Earth		2018-04-23
		will pose la question : the formula for figuring the earth's curve goes against logic, looking at a fixed point and backup 1mi. the point drops 8" then 16" in the next mi. and 32" in the third mi. why shouldn't it be 24" why is the 8" per mi. squared can you tell me in laymens terms why this is it goes against logic it would seem the correct wat would be to add up 8" per mile as you back up from the fixed point 8"- 16"- 24"- 32" not 8/16/32/64" Harley Weston lui répond.
	The derivative of f(x)=2^x/x		2017-11-28
		Chhavi pose la question : f(x)=2^x/x. Find f'(x). Penny Nom lui répond.
	Heat equation		2017-11-23
		Max pose la question : What does du\dt=a(triangle)^2u mean. Can it be solved for t. Penny Nom lui répond.
	A tangent to a curve		2017-10-22
		Jasem pose la question : Suppose that f(x)=(3x-3)^1/2. (A) Find an equation for the tangent line to the graph of f(x) at x=2 (B) Find all values of xx where the tangent line is horizontal, and enter them as a comma-separated list (e.g., 2,-3,6). If there are none, enter none. Values of x Penny Nom lui répond.
	The derivative of the inverse of a function		2016-10-28
		Kate pose la question : Hi, I'm in a College level Calculus course and I can't seem to figure out the answer to this question. Find the derivative of f^-1(4) if f(3)=4 and f'(3)=1/7 Penny Nom lui répond.
	Implicit differentiation		2016-06-06
		Pranay pose la question : Is a circle x^2+y^2=2 a function? If it is not a function, why is it possible to do implicit differentiation on it? Thanks. Penny Nom lui répond.
	The derivative of x!		2016-04-16
		Sang pose la question : How to find the derivative of x! and integral of x! Penny Nom lui répond.
	Prove the earth is round		2016-01-30
		Kevin pose la question : Working on a project for a science fair. To prove the earth is round without the ability to get way above the surface. How could we set up and experiment to see the curve. My thought is using a telescope at the beach? Form what we see so far the curve is 8 inches per mile? So thought is set up a telescope and a target 1 mile away? Robert Dawson and Chris Fisher lui répond.
	A tangent line to a parabola		2015-12-02
		pei pose la question : Given that the line y=mx-5 is a tangent to the curve y=2x^2+3 find the positive value of M. Penny Nom lui répond.
	How much does the Earth curve over a one foot distance?		2015-11-24
		Sean pose la question : Hi, I am trying to figure out how much the earth curves over a one foot distance. I'd like to be able to draw the exact arc on a piece of paper. I am an artist and am looking to make glass vessels with the exact curvature of the earth. I read on your site that it curves approximately 8 inches per mile. can I just use simple ratios to break it down into inches?? Thank you so much for your help. Harley Weston lui répond.
	The derivative of x^1/3		2015-11-08
		omar pose la question : hi can help me am teacher ask me about x^1/3 Derivation definition . Penny Nom lui répond.
	Two cars approaching an intersection		2015-04-16
		Engabu pose la question : Car A is traveling west at 50km/h & car B is traveling north at 60km/h. both are headed for the intersection of the two roads. At what rate are the cars approaching each other when car A is 3km & car B is 4km from the intersection? Penny Nom lui répond.
	Constructing a box of maximum volume		2015-04-14
		Margot pose la question : I need to do a PA for maths and I'm a bit stuck. The PA is about folding a box with a volume that is as big as possible. The first few questions where really easy but then this one came up. 8. Prove by differentiating that the formula at 7 does indeed give you the maximum volume for each value of z. Penny Nom lui répond.
	Angles of elevation and depression		2015-03-08
		Timmy pose la question : Joel is walking down a street and sees a 115 ft tall building in front of him. He stops 190 feet from the base of the building at the tip of the building's shadow. Round answers to three decimal places. A. If there was a piece of rope from the top of the building to Joel, how long would it be? B. What is the angle of elevation from Joel to the top of the building? C. Margaret says that she could find the angle of depression from the top of the building to Joel by subtracting the angle of elevation from 90°. Is she correct? Explain. Penny Nom lui répond.
	The height of a building		2015-01-20
		Emily pose la question : A man 2m high observes the angle of elevation to the top of the building to be 70 degrees. And the angle of depression to the bottom of the building to be 19 degrees. How tall is the building? Robert Dawson lui répond.
	Curvature of the Earth		2014-12-29
		Jimmy pose la question : Both batteries died in my scientific calculator and I have lost my formula for the heigth of the curvature of the earth between two points on the surface. I used degrees and miles. I only had to enter the distance between the two points on the surface and the formula gave me the hieght the earth raised between the two points. Robert Dawson lui répond.
	A ladder against a wall		2014-07-09
		thabo pose la question : A ladder 6.5m long,leans against a wall so that the top of the ladder is 4.8m from the ground.what is the angle of elevation of the ladder to the top of the wall Penny Nom lui répond.
	Differentiate ln[x(2x-4)^1/2]		2014-06-28
		Igwe pose la question : If y=In[x(2x-4)^1/2],find dy/dx at x=3 Penny Nom lui répond.
	The derivative of sin(x)		2014-04-26
		Lucky pose la question : f(x)=Sin(x), by first principle its f'(x)...show me how to solve such problem. Penny Nom lui répond.
	Curvature of the Earth		2014-03-28
		Max pose la question : Recently I read the answer to a question proposed by someone on this site. The question : What is the rate of curvature per mile on Earth? The answer given : Use Pythagoras' Theorem to solve for the answer, given a 1 mile side and a side as the radius. The hypotenuse minus the radius is your answer of drop/mile or curve/mile. My conjecture : Why go through all of that work if the distance is one? Something like {1/diameter} would would fine for such a problem. Seems like a lot of work for no reason. I understand the practical application of Pythagoras' Theorem in this certain situation, as you would need to use a^2+b^2=c^2 for any distance greater than one [mile].. It just seems excessive and unnecessary if you're solving for curve / one mile. Robert Dawson lui répond.
	The domain of a derivative		2013-10-10
		Renee pose la question : I am looking to find the domain of a derivative of a radical function, one such as: f(x) = the square root of (8 − x). I am kind of unclear on how domains work for derivative. I don't understand how you take a function's domain and use that to find the derivative's domain. Thanks! Penny Nom lui répond.
	Equal ordinate and abscissa		2013-08-15
		sonit pose la question : the slope of tangent to the curve y=(4-x^2)^1/2 at the point, where the ordinate and abscissa are equal, is Penny Nom lui répond.
	Distance as a function of acceleration		2013-07-10
		Tom pose la question : If you start at a stoplight and your acceleration is 16t - t^2, how far have you gone after 8 seconds? Penny Nom lui répond.
	The angle of elevation of the sun		2013-07-03
		Maurice pose la question : A vertical pole with a length of 7m cast a shadow with a length of 5m. Calculate the angle of elevation of the sun and include a diagram. Penny Nom lui répond.
	f(x) + f ''''(x)=0		2013-03-05
		Andreea pose la question : Hei. I don’t speak lot of english but here is my question,hope u understand: f(x) + f ````(x)=0. so, my question. what is f(x), where f ````(x) is f(x) derivative by four time ? i tried to find the answer and i knew f(x) is something like that f(x)=e^x*sinx but miss something. Brennan Yaremko lui répond.
	The angles of elevation and depression		2012-12-03
		Chelsey pose la question : a person on a balcony of one building looks towards a second building. if the angle of elevation to the top of the second building is 25 degrees, the angle of depression to the bottom of the second building is 17 degrees, and the balcony of the first building is 22 feet above the ground, what is the height of the second building? Penny Nom lui répond.
	The derivative of y = sin (30º + x)		2012-11-07
		Saskia pose la question : derivative of y = sin (30º + x) Harley Weston lui répond.
	Differentiation rules		2012-10-23
		Morgan pose la question : Use the derivative rules to differentiate each of the following: 1. f(x)=1/x-1 2. f(x)= sqrt(x) Penny Nom lui répond.
	The height of a building		2012-09-08
		Lin pose la question : How do surveyors determine a height of a building 150 feet away with an observation angle at 40 degrees? What is the elevation of that top floor? Penny Nom lui répond.
	5 + 5 + 5 - 5 + 5 + 5 - 5 + 5 x 0 =		2012-07-29
		Tom pose la question : 5 + 5 + 5 - 5 + 5 + 5 - 5 + 5 x 0 = Harley Weston lui répond.
	The angular elevation of the sun		2012-07-14
		VINEET pose la question : WHAT IS ANGULAR ELEVATION OF THE SUM Penny Nom lui répond.
	The derivative of 2sin cubed x - 3 sin x		2012-03-25
		holly pose la question : suppose f(x) = 2sin cubed x - 3 sin x show that f 1(x) = -3 cos x cos 2x Harley Weston lui répond.
	Integral 1/(25-x^2)^3/2		2012-02-22
		John pose la question : Integral 1/(25-x^2)^3/2 Harley Weston lui répond.
	Dt[sin t tan (t^2+1)]		2012-02-21
		Ayu pose la question : Ayu Dt[sin t tan (t^2+1)] derivatives Harley Weston lui répond.
	The curvature of the earth		2012-02-08
		sean pose la question : Question from sean, a student: Two people 1.8 metres tall walk directly away from each other until they can no longer see each other (due to the curvature of the earth, which has a radius of about 6378 km). A) Find a function relating the height of two identical objects with the distance between them using the scenario above as an example. B) Sketch this function (you may use Graphmatica if you wish). Over what domain and range does the function exist? C) Describe this relation in practical terms. Harley Weston lui répond.
	Notation for the second derivative		2012-02-06
		Shafira pose la question : In all math textbooks, it is written that d/dx ( d/dx) (y)= d2y/dx2. Why do they write it as d2y/dx2, not as d2y/d2x2? Robert Dawson lui répond.
	The derivative of x^-(1/2)		2012-01-14
		Eric pose la question : I have an problem figuring out the derivative of the negative square root of x i.e. x^-(1/2) using the first principle. Could someone please show me? Thanks in advance! Harley Weston lui répond.
	Implicit differentiation		2011-10-20
		Monica pose la question : Find dy/dx in terms of x and y, if sin(xy)=(x^2)-y. Penny Nom lui répond.
	The derivative of f(x) = (x+1)^1/2		2011-09-05
		Carla pose la question : Find the derivative using the limit process of f(x) = (x+1)^1/2 Harley Weston lui répond.
	An antiderivative of the square root of (8t + 3)		2011-04-19
		Caitlyn pose la question : I know how to take an antiderivative. But this one's stumping me. I need it to finish a problem. What's the antiderivative of the square root of (8t + 3) ~Caitlyn= Penny Nom lui répond.
	A stone is dropped into a lake		2011-03-24
		AnneMarie pose la question : A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 25 cm/s. Find the rate at which the area within the circle is increasing after 4s. Penny Nom lui répond.
	What is the height of the building?		2011-02-05
		Myra pose la question : The angle of elevation is 45 degrees. The distance from George's foot to the top of the building is 50m. What is the height of the building? Penny Nom lui répond.
	Angle of elevation		2010-12-10
		PANKAJ pose la question : angle of elevation of the sun perpendicular72 and base 88 find angle Penny Nom lui répond.
	A building and a flag pole		2010-09-09
		paul pose la question : A flag pole and a building stand on the same horizontal level. From the point p at the bottom of the building,the angle of elevation of the top t of the flag pole is 65 degrees. From the top q of the building the angle of elevation of the point t is 25 degrees.If the building is20 meters high. Calculate the distance pt Penny Nom lui répond.
	80,000 yards of dirt		2010-08-12
		Jeremy pose la question : If I have an area 50' x 1200', what would be the elevation with 80,000 yards of dirt on it. Robert Dawson lui répond.
	The integral of (x^2*exp(x)/(exp(x)-1)^2		2010-08-09
		sujoy pose la question : please find this integral for me int(x^2*exp(x)/(exp(x)-1)^2 Robert Dawson lui répond.
	Using the limit definition		2010-06-06
		Meagan pose la question : Using the limit definition find the derivative of 3/(2x^2) Harley Weston lui répond.
	Curvature of the Earth		2010-05-29
		grant pose la question : if you have 2 plumb structures 10ft. tall, how far apart will they be when they are 1 inch out of parallel at the top Tyler Wood lui répond.
	Line of sight		2010-05-06
		David pose la question : I live in St. Joseph, Michigan and there is an ongoing argument regarding line-of-sight over the horizon. Standing on a 200 foot high bluff here, people swear they can see the top of the Willis (nee Sears) Tower in Chicago, which is about 1653 feet high. It is my contention that this is actually a "refracted reflection" and not direct-line-of-sight. So, to settle the argument, I'd sure like some simple explanation for this, even if-and I hope not-I am incorrect. David Harley Weston lui répond.
	The height of a flag shaft		2010-04-25
		Sarah pose la question : A man standing 20metres away from a tower observes the angles of elevation to the top and bottom of a flag shaft standing on the tower as 62degrees and 60degrees respectively. Calculate the height of the flag shaft.' Penny Nom lui répond.
	The derivative of y=x^x		2010-04-09
		David pose la question : So, its David, and I was wondering about the derivative of y=x^x. I have often seen it be shown as x^x(ln(x)+1), but when I did it through limits it turned out differently. Here's what I did: It is commonly know that df(x)/dx of a function is also the limit as h->0 of f(x+h)-f(x)/h. To do this for x^x you have to start with lim h->0 ((x+h)^(x+h)-x^x)/h. The binomial theorem then shows us that this is equal to lim h->0 (x^(x+h)+(x+h)x^(x+h-1)h+...-x^x)/h This is also equal to lim a->0 lim h->0 (x^(x+a)+(x+h)x^(x+h-1)h...-x^x)/h. Evaluating for a=0 you get lim h->0 (x^x+(x+h)x^(x+h-1)h...x^x)/h Seeing as the last 2 terms on the numerator cancel out you can simplify to a numerator with h's is each of the terms, which you can then divide by h to get: lim h->0 (x+h)x^(x+h-1)... which when evaluated for h=0 gives us: x(x^(x-1)). This statement is also equal to x^x. This contradicts the definition of the derivative of x^x that is commonly shown. So, my question is: can you find any flaws in the logic of that procedure? I do not want to be shown how to differentiate x^x implicitly because I already know how to do that. Robert Dawson lui répond.
	The derivative of cos^3x		2010-04-06
		Erson pose la question : Find y' of the given function: y = cos^3x. Harley Weston lui répond.
	How far apart are the two girls?		2010-01-18
		benny pose la question : Debby and john are looking up at their house from the backyard. From Debby's point of view, the top of the house is at an angle of elevation of 40 degrees From Johns point of view, directly closer to the house, it is 60 degrees. The house is 15m high. How far apart are the two girls? Robert Dawson lui répond.
	The second derivative of y = x³ (x² + 5)		2009-12-14
		Kyrie pose la question : Find d²y/dx² for this function: y = x³ (x² + 5) Penny Nom lui répond.
	Graphing y=(4-x^2)^5		2009-10-25
		natalie pose la question : I want to graph the curve of y=(4-x^2)^5 without using a graphing calculator. To do this, I'm suppose to find: domain, y and x intercepts, asymptotes, intervals of increase/decrease, local max/min, concavity and points of inflection. I got all the way to the step where I'm solving the concavity and I'm stuck. I found the f"(x) and it came out to be really large polynomial. I want to know how I can solve for the x of f"(x) without the use of a graphing calculator, when the polynomial has x^6 and x^8. Thank you so much, natalie Harley Weston lui répond.
	Differentiating y= square root(x-1)		2009-09-29
		edith pose la question : describe the x-values at which f is differentiable. y= square root(x-1) Penny Nom lui répond.
	An antiderivative problem		2009-08-13
		Indrajit pose la question : ∫4e^x + 6e^-x/(9e^x + 4e^-x)dx = Ax + Bloge(9e2x - 4) + C then A=?......B=?.....C=? plz solve it...."^" stands for "to the power of".... Harley Weston lui répond.
	Application of Derivatives of Trig Functions		2009-05-21
		Alannah pose la question : I have a word problem from my Calculus textbook that I can't figure out. Triangle ABC is inscribed in a semicircle with diameter BC=10cm. Find the value of angle B that produces the triangle of maximum area. I am supposed to set up an equation for the area of the triangle A=b x h/2 using Trig functions based on angle B to represent the base and height but I'm not sure how to do this when the side length given is not the hypotenuse. Janice Cotcher lui répond.
	A vertical radio tower is located on the top of a hill		2009-04-21
		Rafael pose la question : A vertical radio tower is located on the top of a hill that has an angle of elevation of 10 degrees. A 70-foot guy wire is attached to the tower 45 feet above the hill. a. Make a drawing to illustrate the situation b. What angle does the guy wire make with the side of the hill? c. How far from the base of the tower is the guy wire anchored to the hill? What confuses me about this problem is the visual situation. Isn't the angle of the guy wire with the side of the hill the same as the angle of elevation? And if not, then how is one supposed to find the other angles without any more information? Harley Weston lui répond.
	The derivative using limits		2009-04-21
		Kirstin pose la question : I am trying to take the limit of f(x) = [f(x+h)-f(x)] / h If you try taking the limit by substituting the limiting value h=0, you get 0/0, which of course is not the right answer. You rewrite f(x+h)-f(x) so it has a factor of h in it, which you cancel with the h in the denominator before you substitute h=0. But I am not sure how to do this. Thanks. Robert Dawson lui répond.
	The second derivative of h(x)=f(g(x))		2009-02-16
		Kristina pose la question : If h(x)=f(g(x)), and is differentiable, then find h"(x). Robert Dawson lui répond.
	A definite integral		2009-02-09
		Mathata pose la question : Evaluate: integral from 0 to 1, x^2 e^x^3dx Harley Weston lui répond.
	What's the derivative of y = e^2x-e^-2x / e^2x+e^-2x?		2009-02-02
		Heather pose la question : What's the derivative of y = e^2x-e^-2x / e^2x+e^-2x ? Harley Weston lui répond.
	Partial derivatives		2009-01-17
		Meghan pose la question : I have a question I've been working at for a while with maxima/minima of partial derivatives. "Postal rules require that the length + girth of a package (dimensions x, y, l) cannot exceed 84 inches in order to be mailed. Find the dimensions of the rectangular package of greatest volume that can be mailed. (84 = length + girth = l + 2x + 2y)" Harley Weston lui répond.
	Negative rate of change		2009-01-12
		hemanshu pose la question : when i have to find rate of change of decrease in any value my ans comes in negative why?????????? Penny Nom lui répond.
	Determine y'' by implicitly differentiating twice		2009-01-04
		Walter pose la question : Given x^3 - 3xy + y^3 = 1 , determine y'' by implicitly differentiating twice. I cannot solve this. Would you be kind enough to perform the mathematics and show the steps involved in obtaining the solution? Harley Weston lui répond.
	Confusion in a multiple choice question		2008-11-14
		BJ pose la question : My son got this math problem which he could mostly solve. Here it is: The highest location in a certain country is 4525 m above sea level. The lowest point in the same country is 192 m below sea level. a) Find the difference of the two elevations. His answer: a-(-b)= a+b or 4525-(-192)= 4525+192=4717 m. No problem. b) A city is 2221 m above sea level. Is this elevation closer to the highest point or the lowest point? His answer: highest point because: 4525-2221= 2304 m (closest to the highest point) and 2221-(-192)=2221+192= 2413 m. (farthest to the lowest point). OK so far. But then he was given 4 choices for this question with no other information: a) 4717 m; lowest b) 4333 m; lowest c) 4333 m; highest d) 4717 m; highest What does it mean? What's the connection with the rest of the problem? Harley Weston lui répond.
	Antiderivative of 1/(x(1 - x))		2008-10-22
		Matt pose la question : derivative of dx/(x(1-x)) From what I've seen I should break apart the equation as such derivative of dx/x - dx/(1-x) and then get the 2 corresponding log functions. If that is correct why does this factoring work, if that is incorrect what is the proper way to find the derivative. Harley Weston lui répond.
	Concavity and the second derivative		2008-10-15
		Christina pose la question : I'm having trouble solving for a second derivative for the following graphing question. f(x) = (X^2+2x+4)/2x using the quotient rule, I found: f'(x) = (x^2-4)/(2x^2) however, using the quotient rule again I can't seem to solve it (concavity): f'''(x)=[(2x)(2x^2)-(x^2-4)(4x)]/[(2x^2)^2] f''(x)=[(4x^3-(4x^3 -16x)]/4x^4 f''(x)=16x/4x^4 f''(x)=4/x^3 and making the equation equal to zero result in 0=4 which doesn't seem to make sense... Penny Nom lui répond.
	How tall is the wall?		2008-09-29
		ash pose la question : you and bob are separated by a tall wall you stand 10 feet further from the wall than bob your angle of elevation is 37 degrees and his 44 degrees how tall is the wall? Penny Nom lui répond.
	What is the derivative of (2^sinx)/(logbase4(2x+1))?		2008-09-16
		Jesse pose la question : What is the derivative of (2^sinx)/(logbase4(2x+1)) Harley Weston lui répond.
	Angle of elevation		2008-09-09
		kristy pose la question : A man on the tenth floor of a building shouts down to a person on the street. If the angle of elevation from the street to the man in the building is 35° and the man in the building is 40 feet up, about how far away from the building is the person on the street? Penny Nom lui répond.
	The height of a tree		2008-09-09
		danice pose la question : At a certain time of day, the angle of elevation of the sun is 30°. A tree has a shadow that is 25 feet long. Find the height of the tree to the nearest foot. Penny Nom lui répond.
	f(x)=sin^3(3x^2) find f ' (x)		2008-04-21
		Michael pose la question : f(x)=sin^3(3x^2) find f ' (x) Harley Weston lui répond.
	f(x) =ax^blnx		2008-04-13
		charles pose la question : supposef(x) =ax^blnx is a real- valued function. Determine exact values(not decimal approximations) fro nonzero constants a and b so that the function f has a critical point at x=e^3 and a maximum value of 1/2e Harley Weston lui répond.
	The chain rule		2008-04-10
		joey pose la question : pls help me to Differentiate y=(3x^2-4x)^8 Harley Weston lui répond.
	Distance seen		2008-03-18
		Nev pose la question : formule: Distance Seen S = 1.225 x square root of H S = Distance seen in Miles H = Height in Feet What dose 1.225 Relate To ? Stephen La Rocque lui répond.
	Angle of Elevation		2008-01-29
		Rita pose la question : Uluru or Ayers Rock is a sacred place for Aborigines of the western desert of Australia. Chun-Wei uses a surveying device to measure the angle of elevation to the top of the rock to be 11.5 degrees. He walks half a mile closer and measures the angle of elevation to be 23.9 degrees. How high is Ayers Rock in feet? Stephen La Rocque lui répond.
	Differentiate		2007-12-28
		taiwo pose la question : i am finding it difficult to use first principle to differentiate this question: y=xcos2x. can u help me. Penny Nom lui répond.
	A curve sketch		2007-11-22
		Ahson pose la question : Find critical points, determine the monotonicity and concavity and sketch a graph of f(x) with any local maximum, local minimum and inflection points labeled: 1. f(x) = x^4 - x^3 - 3x^2 + 1 Harley Weston lui répond.
	The derivative		2007-11-19
		ralf pose la question : Find the derivative of the function 1-. y=1+2x8 2-. y=(1+2x )8 Harley Weston lui répond.
	f(x+y) = f(x) + f(y) + 2xy		2007-11-01
		Marcia pose la question : For all real numbers x and y, let f be a function such that f(x+y) = f(x) + f(y) + 2xy and such that the limit as h -> 0 of f(h) / h = 7, find: f(0), use the definition of the derivative to find f'(x), and find f(x). Penny Nom lui répond.
	How to solve related rates problems		2007-10-27
		David pose la question : Can you plz explain how and where you come up with an equation to solve this? Find the rate of change of the distance between the origin and a moving point on the graph of y = sin x if dx/dt = 2 centimeters per second. Stephen La Rocque lui répond.
	The derivative of f(x)=1/(x-1)		2007-09-21
		Michelle pose la question : im having trouble finding the derivative of f(x)=1/(x-1) using the f(x+h)-f(x)/h method. Stephen La Rocque lui répond.
	Differentiate x^(1/3) using first principles		2007-09-14
		Sheila pose la question : our teacher gave us this question as a challenge and even he couldnt figure it out: Differentiate x^(1/3) [aka the cube root of x] using first principles. i know the answer is 1/(3.x^2/3), but how is it possible using first principles? Harley Weston lui répond.
	The elevation of the sun		2007-09-10
		Elena pose la question : The "angle of elevation" of an object about you is the angle between a horizontal line of sight between you and the object. (See figure) After the sun rises, its angle of elevation increases rapidly at first, then more slowly, reaching a maximum near noontime. Then the angle decreases until sunset. The next day the phenomenon repeats itself. Assume that when the sun is up, its angle of elevation (E) varies sinusoidally with the time of day. Let t be the number of hours that has elapsed since midnight last night. Assume that the amplitude of this sinsoid is 60 degrees, and the maximum angle of elevation occurs at 12:45 p.m.. Assume that at this time of year the sinusoidal axis is at E=-5 degrees. The period is, of course, 24 hours. a. Sketch a graph of this function b. What is the real-world significance of the t - intercepts? c. What is the real world significance of the portion of the sinusoid, which is below the t-axis? d. Predict the angle of elevation at 9:27 a.m., and at 2:30 p.m. e. Predict the time of sunrise f. As you know, the maximum angle of elevation increases and decreases with the change of the seasons. Also, the times of sunrise and sunset change with the seasons. What one change could you make to your mathematical model that would allow you to use it for predicting the angle of elevation of the sun at time on any day of the year. Harley Weston lui répond.
	The height of a pole		2007-08-02
		lalaine pose la question : Hi, this is my problem.. From a point 50.2 m to the pole, a student measured the angle of elevation to the top of the pole to be 32°. Find the height of the pole if the student's height from his feet to his eyes is about 4 ft. Penny Nom lui répond.
	Using the chain rule to solve a derivative		2007-07-29
		Charles pose la question : I need to find the derivative fo the following function.   _______________________ \/ ______________   \/ (x - 1) / (x + 2) + 1 Stephen La Rocque lui répond.
	Angle of inclination from the horizontal		2007-07-18
		Joyce pose la question : In flying upward for 1260 yards along a straight inclined path airplane rises 156 yards. Find the climbing angle ( the angle of inclination from the horizontal) Thank you in advance Stephen La Rocque lui répond.
	Height of a tower from two observations		2007-07-16
		joyce pose la question : An observer wishes to determine the height of a tower. He takes sight @ the top of the tower from A & B w/c are 5oft. apart @ the elevation on a direct line w/ the tower. The vertical angle @ point A is 30 degrees & the point B is 40 degrees. What is the height of the tower? Find the value of x in angle tangent 40 degrees and 30 degrees? Show the solution of the value of x? Stephen La Rocque lui répond.
	Height of an antenna (angle of elevation)		2007-07-16
		Fhay pose la question : An antenna stands on the edge of the top of a 52 story building from a point 320 ft. from the base of the building, the angle of elevation to the top of the antenna is 64 degrees in each story is 12 ft. high. Find the height of the antenna Stephen La Rocque lui répond.
	The two towers (angles of elevation trigonometry)		2007-07-14
		joyce pose la question : The angle of elevation of tower B from the top of tower A is 28 degrees and the angle of elevation of the top of tower A from the base is 46 degrees Find the height of tower A if tower B is 120 m high? Stephen La Rocque lui répond.
	Implicit Derivatives		2007-07-13
		Charles pose la question : I need help computing y' by implicit differentiation the question is: y^2 + x/y + 4x^2 - 3 Stephen La Rocque lui répond.
	Derivative of a Function		2007-07-09
		Bob pose la question : What is the derivative of the function a sub n = [n/(n+1)]^n ? Stephen La Rocque lui répond.
	Log base 2 of log base 2 of x		2007-06-27
		alex pose la question : y = log base 2 of lag base 2 of x The slope of the tangent to the given curve at its x-intercept is..? Harley Weston lui répond.
	Angles of depression		2007-06-13
		Phonda pose la question : The pilot of a small private plane can look forward and see the control tower for a small airstrip. Beyond that is a large factory that is 3 milies from the airstrip. The angles of depression are 12.5 degrees and 4.8 degrees respectively. Find the airplane's altitude, to the nearest ten feet. Stephen La Rocque lui répond.
	Maximizing the volume of a cone given the slant length		2007-05-14
		Christina pose la question : A coffee filter for a new coffee maker is to be designed using a conical filter. The filter is to be made from a circle of radius 10cm with a sector cut from it such that the volume of coffee held in the filter is maximised. Determine the dimensions of the filter such that the volume is maximised. Stephen La Rocque and Kerstin Voigt lui répond.
	The second derivative		2007-04-14
		Gerry pose la question : In mathematical context,what do you understand by the term "Second Derivative" Penny Nom lui répond.
	y = sin(2x)		2007-03-22
		bader pose la question : sin(2x) find dx/dy Penny Nom lui répond.
	Angle of elevation		2007-03-13
		Joslyn pose la question : A ship at sea sights a 12m high lighthouse on a cliff which is 80m above sea level. If the angle of elevation to the top of the lighthouse is 27 degrees, calculate the distance from the ship to the shore. Haley Ess lui répond.
	An excavation		2007-03-07
		Brandon pose la question : you have and excavation area 140' long by 20' wide by 3' deep. What is the excavated volume? Penny Nom and Brennan Yaremko lui répond.
	Angle of elevation		2007-02-05
		Zee pose la question : A 55 ft. flagpole casts a 25 ft. shadow. Calculate the angle of elevation to the sun to the nearest degree. Stephen La Rocque lui répond.
	Derivatives		2007-02-01
		Jacob pose la question : Find the derivative of: y= pi^2+x^2+3xy+sin(y^2) Penny Nom lui répond.
	Percent elevation gain		2007-01-24
		Susan pose la question : okay... so if I hike Gregory Canyon and it's a 1.1 mile hike with a 900 foot elevation gain, what's the percent elevation gain? Stephen La Rocque lui répond.
	Differentiate Y= sin3x + cos7x		2006-08-22
		james pose la question : Differentiate the function of x using the basic rules. Y= sin3x + cos7x Stephen La Rocque lui répond.
	livinia the housefly finds herself caught in the oven		2006-06-27
		Danielle pose la question : livinia the housefly finds herself caught in the oven at the point (0,0,1). the temperature at the points in the oven is given by the function T(x,y,z) = 10 (xe(-y2) + ze(-x2)) where the units are in degrees celsius. (i.)so if livinia begins to move towards the point (2,3,1) at what rate in deg/cm does she find the temp. changing? (ii.)in what direction should she move in order to cool off as rapidly as possible? (iii.)suppose that livinia can fly at a speed of the square root of 2 (cm/sec.) if she moves in the direction of part (ii) at what rate will she find the temp. to be changing? Penny Nom lui répond.
	differentiate the volume of a cylinder with V respect to h		2006-05-24
		A student pose la question : differentiate the volume of a cylinder with V respect to h Stephen La Rocque lui répond.
	Rate of ladder falling		2006-04-30
		Harsh pose la question : A ladder 4 m long rests against a vertical wall. If the bottom of the ladder slides away from the wall at a speed of 30 cm/s, how quickly is the top of the ladder sliding down the wall when the bottom of the ladder is 2 m from the wall? Stephen La Rocque lui répond.
	The waterway between Lake Huron and Lake Superior		2006-03-21
		Trenae pose la question : the waterway between lake huron and lake superior separates the u.s and canada.it is usually 13 feet above the water when its closed and each section is 210 feet long if the angle of elevation is 70 degrees then what is the distance from the top of the drawbridge to the water and the width of the gap created by the 2 sections of the bridge Penny Nom lui répond.
	Differentiation, powers and logs		2006-01-06
		Claudia pose la question : Question: how do I find the derivative of x* ln(x+(e^2))^2 x^lnx x^(e^(-x^2)) Penny Nom lui répond.
	Two word problems		2005-11-14
		Jennifer pose la question : 1. Every other person on a school's parent advisory committee is surveyed to determine how many people support passage of a school bond to build a new elementary school. Is this a good sample? Why or why not? 2.What is the difference in elevation between the highest point in California,Mount Whitney,which towers 4421 meters above sea level, the lowest point in California,Death Valley, which lies 86 meters below sea level? Harley Weston lui répond.
	The elevation of the top of the house		2005-11-13
		Chloe pose la question : Karen is standing 23 metres away from the base of a 23 metre high house. Assume that Karen's eyes are 1.5 metres above ground. Find the elevation of the top of the house from Karen's eye line. Penny Nom lui répond.
	Notation for the second derivative		2005-11-08
		Mussawar pose la question : my question is d/dx( dy/dx) = d2y/dx2. why it is not equal to d2y/d2x. Penny Nom lui répond.
	Velocity and acceleration		2005-10-27
		Candace pose la question : When taking the integral of the position function, you get the velocity function, and the same for velocity to acceleration. So when you do each of these, you get a function. But when you integrate on a graph, you get an area under a curve. The area is un units squared- where do the units go when you make it an equation? How can a function be an area? Harley Weston lui répond.
	Can we take the derivative of independent variable		2005-10-18
		Mussawar pose la question : why we take derivative of dependent variable with respect to independent variable .can we take the derivative of independent with respect to dependent.if not why. Walter Whiteley lui répond.
	How do you differentiate y=(x)^(x^x)?		2005-09-14
		Calebius pose la question : How do you differentiate y=(x)(xx)? Penny Nom lui répond.
	Differentiating F(x,y) = 0		2005-01-23
		Jacob pose la question : In calculus, we often mention to the students that if F(x,y) = 0, then we can differentiate both sides and still get an equality. The problem is that we can't perform the same operation on F(x) = 0, say x = 0, otherwise 1 = 0, which is absurd. What is the reason? Walyer Whileley and Harley Weston lui répond.
	ln(x)/x		2004-12-11
		Tina pose la question : What is the derivative of (ln x)/x? The double derivative? Penny Nom lui répond.
	The third derivative		2004-10-15
		Holly pose la question : Why would you ever take the third derivative? Harley Weston lui répond.
	differentiate Y=X^X^X		2004-09-13
		Kunle pose la question : differentiate Y=X^X^X Penny Nom lui répond.
	Differentiation		2004-08-04
		A parent pose la question : I am a parent trying to understand higher level of maths and would be very grateful if you could help with differentiating the following functions, identifying general rules of calculus: a) f(x)=e^2^xIn(cos(8x)) b) f(x)=secx/SQRTx^4+1 Penny Nom lui répond.
	Angles of elevation and depression		2004-05-18
		Anjum pose la question : what is the difference between an angle of elevation and angle of depression? Penny Nom lui répond.
	Some calculus problems		2004-04-01
		Weisu pose la question : I have questions about three word problems and one regular problem, all dealing with derivatives. Find all points on xy=exy where the tangent line is horizontal. The width x of a rectangle is decreasing at 3 cm/s, and its length y is increasing at 5 cm/s. At what rate is its area A changing when x=10 and y=15? A car and a truck leave the same intersection, the truck heading north at 60 mph and the car heading west at 55 mph. At what rate is the distance between the car and the truck changing when the car and the truck are 30 miles and 40 miles from the intersection, respectively? The production P of a company satisfies the equation P=x2 + 0.1xy + y2, where x and y are the inputs. At a certain period x=10 units and y=8 units. Estimate the change in y that should be made to set up a decrease of 0.5 in the input x so that the production remains the same. If you could just give me some hints on these questions, I'd really appreciate it. Thanks! Penny Nom lui répond.
	A derivative		2004-03-31
		A student pose la question : What is the nth derivative of f(x) =(2x)/(1-(x2))? Harley Weston lui répond.
	A partial derivative		2004-03-19
		Penny Nom pose la question : Is it possible to differentiate the following equation, if so could you please explain. S=SQRT(T-(5/X^2)) I would like the derivative of S with respect to X. Harley Weston lui répond.
	Acres and square miles		2004-02-17
		Richard pose la question : How many acres are in .17 square miles? and How many acres are in .6 square miles? The two areas I am requesting information about are Vatican City and San Marino, the two smallest countries in the world. If I can transfer the sq. miles into acres , I can relate the size of these countries to our school grounds and the students will better understand their sizes. Penny Nom lui répond.
	Areas, perimeters and derivatives		2004-02-15
		Geoff pose la question : A recent lecture in my calculus class led me to realize that the derivative of the area of a circle, with respect to the radius is equal to the circumfrence. This also holds true for the relationship between the volume of a sphere and the surface area of that sphere: why do these hold true? why is it only for circular objects? Harley Weston lui répond.
	The derivative of x to the x		2004-02-14
		Cher pose la question : what about the derivative of x to the power x? Penny Nom lui répond.
	How far can you see?		2003-12-15
		Judy pose la question : How far apart, assuming no obstacles, can two people stand and still see each other? i know this deals with the curvature of earth, but i can't figure out the formulas involved. Chris Fisher lui répond.
	Functions, graphs and derivatives		2003-10-05
		Jathiyah pose la question : I wanted to know how would you tell (on a graph diplaying two funtions), which funtion is the derivative of the other? Walter Whiteley lui répond.
	The slope of a tangent		2003-10-01
		A student pose la question : find the slope of the tangent to each curve at the given point f(x)=square root 16-x, where y=5 Penny Nom lui répond.
	Hidden by the curvature of the Earth		2003-04-23
		Shirley pose la question : There are 2 six foot men. What would the distance be between them before one could not be seen because of the curvature of the earth? Penny Nom lui répond.
	A two stage rocket		2002-11-26
		Hoda pose la question : a two stage rocket accelerates in free space by ejecting fuel at a constant relative speed , v(ex). the full fuel load makes up 80% of the initial mass of the entire two stage rocket . the rocket accelerates from rest until at the end of the first stage when 75% of its fuel has been burnt. find an expression for the speed of the rocket at the end of the first stage in terms of v(ex). Claude Tardif lui répond.
	The slope of a tangent line		2002-03-04
		Ridley pose la question : Suppose a function f(x) has the line 3x+4y=2 as its tangent line at x=5. Find f'(5). Harley Weston lui répond.
	A tangent line		2001-11-21
		A student pose la question : write an equation of the line tangent to the graph of ey + ln(xy) = 1 + e at (e,1) Harley Weston lui répond.
	4 sinx cosy = 1		2001-10-10
		A student pose la question : How would i differentiate the following example in terms of t (x and y are functions of t) 4 sinx cosy = 1 Claude Tardif lui répond.
	When will the ship disappear?		2001-10-10
		Stacy pose la question : If the sail of a ship were a 100 ft. tall and you were a mouse at the edge of the shore looking out at it, how far out would the ship be when it disappears? ( your eye level is level with the water.) Harley Weston lui répond.
	(x^2-5x-6)/(x-6)		2001-10-02
		Bill pose la question : given f(x) = (x2-5x-6)/(x-6) find f'(6). Harley Weston lui répond.
	Conservation, consumption and population growth		2001-06-04
		Steve pose la question : I'm trying to quantify the relation between conservation/consumption and population growth. For instance let's consider California: The 2000 census states that California's population grew from 29,760* in 4-1990 to 33,871 in 4-2000. I want to find r or rate of growth per year. Based on the exponential growth formula for population growth: . . . Penny Nom lui répond.
	Differentiation		2001-04-17
		Esther pose la question : Could you please tell me what the first derivative is of the following: y = 2/(2x+e2x) Is it (1+xe2x)/(2x+e2x)2 or perhaps -4(1+e2x)/(2x+e2x)2 ? I am a little confused between the two! Harley Weston lui répond.
	The angle of elevation		2001-03-08
		Jeffrey pose la question : At a Certain time, a vertical pole 3m tall cast a 4m shadow. What is the angle of elevation of the sun? Harley Weston lui répond.
	The domain of the derivative		2001-02-22
		Wayne pose la question : I know that the domain of f'(x) is a subset of the domain of f(x). Is it necessarily true that the subset will have at most one less element than the domain of the original function? Harley Wesston lui répond.
	Differentiation of y = x n		2001-02-17
		Jashan pose la question : i am studying differentation at the moment i have drawn some graphs such as y=x 2. i have found the formula for the gradient of this curve, this being 2x obtained by using differentation, but i need to know the general case for the formula where y=xn in order for me to understand this topic more throughly, i would also like to know how u derived this general formula Harley Weston lui répond.
	Motivators		2001-01-16
		Michelle Stapley pose la question : Do you know of any (or where I can find) student motivators for math at the secondary level? Basically any way I can motivate my students to WANT to learn math. Penny Nom lui répond.
	Net, gross and vat		2000-11-20
		Chris pose la question : I have my gross but want to find out the net so I know how much the VAT is? Penny Nom lui répond.
	Concavity		2000-10-22
		Alex pose la question : the question is: on what interval is f(x)=(x2)(ex)? ive found the 2nd derivative which is ex(x2+4x+2) and i did the quadratic to get -2-20.5 and -2+20.5, but i dont know what the interval is. Harley Weston lui répond.
	Derivatives, there must be an easier way		2000-09-06
		Brad Goorman pose la question : The direction read: Take the derivative of each expression. y = {1+[x+(x2 +x3)4]5}6 Harley Weston lui répond.
	A derivative problem		2000-06-04
		Jeff Ellis pose la question : If F(x)=(4+x)(3+2x2)2(2+3x3)3, find F'(0) Harley Weston lui répond.
	Thearcius Functionius		2000-05-03
		Kevin Palmer pose la question : With the Olympics fast approaching the networks are focusing in ona new and exciting runner from Greece. Thearcius Functionius has astounded the world with his speed. He has already established new world records in the 100 meter dash and looks to improve on those times at the 2000 Summer Olympics. Thearcius Functionius stands a full 2 meters tall and the networks plan on placing a camera on the ground at some location after the finish line(in his lane) to film the history making run. The camera is set to film him from his knees(0.5 meters up from the ground) to 0.5 meters above his head at the instant he finishes the race. This is a total distance of two meters(the distance shown by the camera's lens). Harley Weston lui répond.
	An indefinite integral		2000-05-03
		Bonnie Null pose la question : I am to find the indefinite integral of: (ex - e-x)2 dx Claude Tardif lui répond.
	y = x^x^x^x...		2000-04-05
		Michael Hackman pose la question : Find the derivative of: y = x^x^x^x... on to infinity. Claude Tardif lui répond.
	Filling a hole		2000-04-01
		John McNeill pose la question : I have an area 20 feet long and 12 feet wide It starts out at a depth of 4 inches and ends up at 0 inches. How much sand do I need to fill the excavation. Penny Nom lui répond.
	A calculus problem		1999-12-08
		JT Wilkins pose la question : These are the questions: Show that there exists a unique function that meets the following requirements: a) f is differentiable everywhere b) f(0)= f'(0)= 0 c) f(x+y)= f(x)+ f(y), for all real values of x,y Consider the function F: R-->R (All Reals) F(x) = 0, for x irrational & 1/q, x=p/q gcd(p,q)=1 q > 0 a)determine the values x where f is continuous, respectively discontinuous. b)determine the values x when f is differentiable and for each of these values compute f'(x). Penny Nom lui répond.
	The chain rule		1999-12-03
		Jennifer Stanley pose la question : This problem is making me dizzy. I would greatly appreciate a little help! Express the derivative dy/dx in terms of x. y=u^2(u-u^4)^3 and u=1/x^2 Harley Weston lui répond.
	Two calculus problems		1999-12-01
		O'Sullivan pose la question : Question #1 Assume that a snowball melts so that its volume decreases at a rate proportional to its surface area. If it takes three hours for the snowball to decrease to half its original volume, how much longer will it take for the snowball to melt completely? It's under the chain rule section of differentiation if that any help. I've set up a ratio and tried to find the constant but am stuck. Question #2 The figure shows a lamp located three units to the right of the y-axis and a shadow created by the elliptical region x^2 + 4y^2 < or= 5. If the point (-5,0) is on the edge of the shadow, how far above the x axis is the lamp located? The picture shows an x and y axis with only the points -5 and 3 written on the x axis. the lamp is on the upper right quadrant shining down diagonally to the left. There's an ellipse around the origin creating the shadow. It's formula is given as x^2 + 4y^2=5. Harley Weston lui répond.
	Two derivatives		1999-11-16
		Gina Renicker pose la question : The derivative of: y=e(xlnx) and y=x2arctan(x1/2) Harley Weston lui répond.
	Ben's observation		1999-10-28
		Emily Nghiem and Ben Rose pose la question : As a teacher at a school called Educere in Houston, I have a ninth-grade student who discovered the following shortcut last year as an eight-grader. What he noticed is that given any two consecutive integers (or n and n+1 for any rational number greater than or equal to 2), the difference between their squares was equal to the sum of the two numbers. . . Chris Fisher and Penny Nom lui répond.
	Clockwise or Counterclockwise?		1999-10-27
		Tim pose la question : A particle moves around the circle x2 + y2 = 1 with an x-velocity component dx/dt = y Find dy/dt Does the particle travel clockwise or counterclockwise around the circle? Why? Harley Weston lui répond.
	Derivatives with logs		1999-10-26
		Kate pose la question : What is the derivative of 5 to the 5x-2 at x equals 0.8? Harley Weston lui répond.
	Parametric Equations		1999-08-06
		Nicholas Lawton pose la question : Show that an equation of the normal to the curve with parametric equations x=ct y=c/t t not equal to 0, at the point (cp, c/p) is : y-c/p=xp^2-cp^3 Harley Weston lui répond.
	A calculus problem		1999-07-22
		Nicholas Lawton pose la question : The curve y= e^x(px^2+qx+r) is such that the tangents at x=1 and x=3 are parallel to the x-axis. the point (0,9) is on the curve. Find the values of p,q and r. Harley Weston lui répond.
	Graphing the Derivative		1999-01-18
		Milena Ghebre pose la question : This question has been nagging me for sometime now. Is there a way of finding out the derivative of a function, just by looking at the graph of it? Walter Whiteley lui répond.
	Calculus		1999-01-16
		Kaylea Rankin pose la question : Differentiate the following. y = 1 /(2+3/x) Jack LeSage and Penny Nom lui répond.
	The area and the circumference of a circle.		1998-08-27
		Jason Wright pose la question : I was looking at the relationship of the area of a circle and the circumference when I realized that 2*pi*r is the derivative of pi*r^2. I was wondering if there is any connective deep dark meaning as to why this appears to be related. Thanks for any help you can give me! Walter Whiteley lui répond.
	Curvature of the Earth		1998-03-16
		Robert Dyck pose la question : How can I find the curvature per mile of the earths surface? What is it? Harley Weston lui répond.
	A Tightrope Walker.		1998-02-19
		Amy Zitron pose la question : A tightrope is stretched 30 feet above the ground between the Jay and the Tee buildings, which are 50 feet apart. A tightrope walker, walking at a constant rate of 2 feet per second from point A to point B, is illuminated by a spotlight 70 feet above point A.... Harley Weston lui répond.
	Mathematical Induction and the Derivative		1997-03-18
		Shuling Chong pose la question : "Obtain a formula for the nth derivative of the product of two functions, and prove the formula by induction on n." Any educated tries are appreciated. Penny Nom lui répond.

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