







Les dérivées partielles 
20120516 

Haddouche pose la question : Bonjour,
Je vous demande de bien vouloir m'éclaircir comment on calcule les dérivées partielles généralement étudiées dans les modèles de la concurrence fiscale à titre d'exemple celui de Wildasin ""NASH EQUILIBRIA IN MODELS OF TAX COMPETITION "", dont j'ai essayé toutes les méthodes et aucune d'elle n'est arrivée à trouver le résultat des dérivées de ce dérnier papier, à cet effet, je vous serais reconnaissant de m'éclaicir la méthode afin de résoudre ce problème qui pour moi un vrai mistère à percer.
Je vous remercie infiniment à l'avance.
Et comptant sur votre compréhension, mes salutations les meilleures.
HA Claude Tardif lui répond. 





le prix de départ 
20060910 

un élève pose la question : Une jupe coûte 36 euros après une démarque de 20% quel est le prix de départ moi j'ai trouvé 45 euros mais je n'ai pas la formule de calcul exacte Claude Tardif lui répond. 





Partages inégaux 
20050929 

Un eleve pose la question : Alex et julie ont ensemble 4728 . euro Si Alex donne 538. euro à Julie, ce dernier aurait alors le triple de Julie. Quelle est la somme possédée de chacun? Claude Tardif lui répond. 





Marie achète un croissant et une tartelette 
20040201 

M. et Mme Simoneton pose la question : Marie achète un croissant et une tartelette. Elle paie 1,64 €
Isabelle achète un croissant et un pain au chocolat. Elle paie 1,51 €
Marc achète un poain au chocolat et une tartelette. Elle paie 1,77 €
Trouver le prix d'un croissant, d'une tartelette et d'un pain au chocolat.
Claude Tardif lui répond. 





l'équation d'une rotation dans un graphique cartésien 
20011114 

Ghaith pose la question : je d6sir que vous me rafraichissez un peu la mémoire s.v.p. j'aimerai savoir l'équation d'une rotation dans un graphique cartésien merci Claude Tardif lui répond. 





Point de partage 
20000221 

Sebastian Murciano pose la question : J'aurais besoin de savoir où je peux trouver de l'informations, ou estce que vous pouvez me donner de l'information sur : Point de partage d'un segment étudié en Secondaire 4. Claude Tardif lui répond. 





Derivées partielle 
19991019 

Arnaud Flandin pose la question : Quel est la definition des derivées partielle Claude Tardif lui répond. 





Renting an electric cart 
20170107 

Desiree pose la question : Vacation Rentals rents electric carts for travel on their grounds. The economy plan rents
carts for $26 per day and the premium plan rents a carts for $12 per day plus a one time fee of $126.05
For how many whole days would it be cheaper to rent from the economy plan then from the premium plan? Penny Nom lui répond. 





A pie chart 
20161205 

vickie pose la question : Determine the central angle needed to form a pie chart for the following housing characteristic data: 63% owner occupied, 27% renter occupied, and 10% vacant Penny Nom lui répond. 





A road trip word problem 
20160410 

Marc pose la question : While on a road trip I imagined this random word problem. Suppose I start a trip of 75 miles. My initial speed is 75 miles per hour. After every mile traveled I decrease my speed by one mile per hour. After the first mile I decrease my speed to 74 miles per hour and so on for each subsequent mile traveled. How long will it take to complete the 75 mile journey? Penny Nom lui répond. 





Compressed Earth blocks 
20160302 

John pose la question : how many 14"x10"x4" blocks do I need for a 1300sq foot house 8 foot high Penny Nom lui répond. 





10800 sq. ft equal approx what part of an acre? 
20160227 

David pose la question : 10800 sq. ft equal approx what part of an acre Penny Nom lui répond. 





Prove the earth is round 
20160130 

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. 





The perimeter of a one quarter acre square 
20160115 

Kerry pose la question : If you have a perfect square that is one quarter of an acre what are the length of the sides and how do you arrive at the solution? thank you, Kerry. Penny Nom lui répond. 





How much does the Earth curve over a one foot distance? 
20151124 

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. 





Partitions into distinct parts 
20150919 

Brian pose la question : Looking for a formula where I can type in a number, 17 for example, and using the numbers 1 through 17 (1, 2, 3, 4 etc....), to come up with all possible combinations, when added, that will equal 17. And each number can only be used once. I've tried a few search engines but my computer stares at me blankly and scratches its head :/. Chris Fisher lui répond. 





The perimeter of a quarter circle 
20150521 

Bethany pose la question : The perimeter of a quarter circle is 3.57. What is the quarter circle's radius? Penny Nom lui répond. 





The perimeter of a quarter circle 
20150410 

Riley pose la question : How do you find the perimeter of a quarter circle when the radius is 56? Penny Nom lui répond. 





Curvature of the Earth 
20141229 

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. 





The perimeter of a quarter circle 
20141226 

Maisy pose la question : This is the question that I got for a math worksheet.
The radius of a quarter circle is 5 miles. What is the quarter circle's perimeter?
Use 3.14 for pi. Penny Nom lui répond. 





An arc subtended at the center of the Earth 
20140720 

Abhinav pose la question : Meerut is 60 km from Delhi. Find the nearest second the angle subtended at the center of the earth by the arc joining these two points,earth being regarded as a sphere of 5940 km radius. Penny Nom lui répond. 





Quarters 
20140704 

kamal pose la question : how many quarters in the sum of 8 and 12 ? Penny Nom lui répond. 





A triangle on the surface of the Earth 
20140626 

Christine pose la question : A, B and C are three towns, the bearing of B and C from A being 310 degrees and 220 degrees, and their distances from A are 510km and 700km respectively. Find the bearing of B from C to the nearest minute. Robert Dawson lui répond. 





A model of the sun and the Earth 
20140614 

Lynn pose la question : There is a model of the sun that is 2 1/2 inches in diameter. This is the only clue we have! How far away is the earth from this model? Penny Nom lui répond. 





Curvature of the Earth 
20140328 

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. 





A cable around the Earth 
20140313 

fikile pose la question : By how much must an equatorial cable be extended in order that it runs 1meter above the ground? Penny Nom lui répond. 





Three investment partners sharing the profit 
20140222 

Ayatullah pose la question : Hello;
We are three partners and bought a property at 2050000 and sold at 2300000.
Details of investment of the partners
X= 1500000
Y= 400000
Z = 150000
My questions are
1) How could i calculate percentage of investment of each partner?
2) How could i deduct 30% commission from each partner in profit?
3) How could i distribute the profit amongst the partners?
Thanks in advance Penny Nom lui répond. 





If the earth was made of a ball of string 
20130918 

Tammy pose la question : My 9 year old son asked me a question and I have no idea how to work it out! Please can you help?
If the earth was made of a ball of string and you unravelled the string how long would it be? Assuming the string is 5mm thick. Penny Nom lui répond. 





Restricted partitions 
20130325 

vidya pose la question : I am having a series of numbers eg.( 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
I can take any 5 digits eg(15,10,8,6,5) and it should not repeat and the summation should be any predefined static value . eg(44)
That is (15+10+8+6+5=44) . How many summation series will result 44 ?
My problem is how to find this using a formula or any other simpler automation method is there instead of checking one by one all the combinations.
Plz do help me... Thnks in advance Chris Fisher lui répond. 





Cumulative Frequency Math Question 
20130320 

Primadonna pose la question :
Hi,
Please help me solve this question.
Thank you so much.
The cumulative frequency table below shows the length of time that 30 students spent text messaging on a weekend.
Minutes Used 
Cumulative Frequency 
3140 
2 
3150 
5 
3160 
10 
3170 
19 
3180 
30 
Which 10minute interval contains the first quartile?
(1) 31–40
(2) 41–50
(3) 51–60
(4) 61–70 Penny Nom lui répond. 





Row echelon form 
20130315 

Shawn pose la question : Please help me put matrix in row echelon form:
1 9 8 0
5 8 1 35
1 4 1 17 Penny Nom lui répond. 





A chart for y=mx+b 
20130311 

jacinda pose la question : how to make a chart for y=mx+b Penny Nom lui répond. 





The zeros of a fourth degree polynomial 
20130123 

Dakota pose la question : My problem has multiple steps and I have done everything but the last one. 8The original problem is f(x)=x^45x^3+7x^2+3x10 and I have to find the zeros of the equation. I used synthetic substitution like my teacher taught us to get the equation of x^33x^2+x+5=0 but now I don't know how to get the zeros of that equation, or solve it. Penny Nom lui répond. 





A bipartite graph 
20121029 

A student pose la question : Suppose that G be a bipartite graph with maximum degree of k.
Prove that:
1)Exists a Kregular bipartite graph that G be subgraph it(H) Claude Tardif lui répond. 





A tank with an inner walled compartment 
20121012 

don pose la question : I have a tank 20 feet diameter, 19' 8" tall with an inner walled compartment that has a 7' 6" radius arc with in the tank. I need to figure out the volume of the inner area and the volume of the larger area. Harley Weston lui répond. 





Points per quarter 
20120514 

debbie pose la question : A basketball team scores 216 points in 8 quarters . Find the teams point per quarters rate Penny Nom lui répond. 





A pie chart 
20120501 

muhammad pose la question : How can i construct a pie chart on the following of the combunation of students:
Sos 50, Crs 25, Eng 100, Iss 75, Geo 150, Hist 10 Penny Nom lui répond. 





A circle inscribed in a quarter circle 
20120220 

sonam pose la question : ABC is a quarter circle and a circle is inscribed in it and if AB=1cm than find radius of a small circle. Penny Nom lui répond. 





The curvature of the earth 
20120208 

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. 





A quartic polynomial that is a perfect square 
20120205 

archit pose la question : If P(x)=x^4+ax^3+bx^28x+1 is a perfect square then (a+b)=? Penny Nom lui répond. 





Two shapes 
20120106 

muhammad pose la question : Question from muhammad, a student:
a boy has two pieces of wire each 99cm long .he bends them into the shapes shown below.calculate the radius of each figure,giving each answer to two decimal places.figures are one is semicircle and other on is half of the semicircle. Harley Weston lui répond. 





The perimeter of a quarter circle 
20111110 

sierra pose la question : how do you figure the perimeter of a quarter circle that has a radius of 12 Penny Nom lui répond. 





Decartes' circle theorem 
20110907 

Joseph pose la question : Given 3 circles of diameters 50, 55, and 60 units,
Place them externally tangent.
What is the diameter of the outer circumscribing circle,
tangent to all 3 circles? I can attach a pdf if this description is not clear.
Not urgent, this has nothing to do with current assignments,
just wondering if I have developed the best methods? Chris Fisher lui répond. 





A tangent to the earth 
20110903 

Vickram pose la question : I have a math problem regarding tangent and circle. My example is as
follows: if a long flat ruler measuring 1500 miles is placed on top of earth
which has a radius of 3960 miles what part (length) of the tangential ruler
will actually be touching the earth and what two parts will not? Chris Fisher lui répond. 





Identify each polynomial by its degree and number of terms 
20110110 

betty pose la question : Write in standard form and identify each polynomial by its degree and number of terms. How do you do this? Penny Nom lui répond. 





The perimeter of a quarter circle 
20101215 

kim pose la question : how do you figure the perimeter of a quarter circle that has a radius of 7 inches? I would like to have the explanation of how you figure it out. Thank you Penny Nom lui répond. 





The angles in an mgon and genrealizations 
20101016 

Michael pose la question : Hello:
In answer to a student's question, someone named Penny from
your organization provided a proof that the sum of the interior
angles of a triangle in the plane is pi radians (or 180 degrees).
I am interested (and I'm sure many other people would be too) in
3 potential generalizations of this basic fact in plane geometry: Walter Whiteley lui répond. 





Area on a dart board 
20101011 

Robert pose la question : A dart board consists of concentric circles and line segment. the radius of the bull's eye is 4 inches and each ring surrounding the bull's eye is 3 inches wide.
a) what is the area of the bull's eye
b) what percent is the bull's eye.
hint there are 4 rings and the bull's eye is divided into 4 (90) degree angles (meaning 1/2 up and down) (1/2 left to right. Stephen La Rocque lui répond. 





Factoring cubics and quartics 
20100929 

Tori pose la question : How do you factor these types of questions:
* x^3  4x^2  x + 4
*2x^3  3x^2  4x  6
*x^4  15x^2  16 Robert Dawson lui répond. 





The volume of earth to be moved 
20100729 

Michael pose la question : Volume of earth moved @ 500' across, 1 to 3 degree slope, 30' deep X 50' across at the bottom. Stephen La Rocque and Harley Weston lui répond. 





Curvature of the Earth 
20100529 

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. 





A quartic equation 
20100518 

Austin pose la question : Z^410z^2=9 Penny Nom lui répond. 





Line of sight 
20100506 

David pose la question : I live in St. Joseph, Michigan and there is an ongoing argument regarding lineofsight 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 directlineofsight.
So, to settle the argument, I'd sure like some simple explanation for this, even ifand I hope notI am incorrect.
David Harley Weston lui répond. 





If a third is a fourth of a number, what is the number? 
20100408 

larry pose la question : If a third is a fourth of a number, what is the number? Penny Nom lui répond. 





If the earth were covered completely with water 
20100225 

don pose la question : If the earth were covered completely with water (over Everest) how many gallons would it be?? Penny Nom lui répond. 





Everything in a cube 2 miles long? 
20100131 

Naresh pose la question : in a book, i got to read this :
Is it possible to pack the entire population of earth and everything that was created by
humankind in a cube whose edges are 2 miles long ?
Is it possible? Thanks. Stephen La Rocque lui répond. 





Matt has 40 coins 
20091118 

Amy pose la question : Matt has 40 coins(nickels, dimes, and quarters). The total amount is $4.05. He has 7
more nickels than dimes. How many quarters does he have? Penny Nom lui répond. 





The integral of sqrt(x) * ln(x) 
20091012 

Oana pose la question : Hi! Can you tell me please how much is : ∫ (√x * ln x) ? Penny Nom lui répond. 





Dart teams 
20090918 

Sally pose la question : I have 14 dart teams. Each team has a home bar.Usually it is one week home, the next week away. I have 3 locations that have one board only, yet have 2 teams at each location. I have one location that has 2 dart boards, and 3 teams. The last location have 3 dart boards and 4 teams.Can you make me a schedule that will be home and away, and every teams plays each other twice. In case you are wondering, the bars sponsor the teams.Thank you. Sally Robert Dawson lui répond. 





Helen has twice as many dimes as nickles. 
20090908 

Dan pose la question : Helen has twice as many dimes as nickles. She has 5 more quarters than nickles. She has $4.75. How many nickles does she have? I know she has 14 dimes, 7 nickles and 12 quarters. How do you put this into an algebra equation? Stephen La Rocque lui répond. 





Nickels, dimes and quarters 
20090902 

danielle pose la question : In changing a $5 bill, Sarah received nine more dimes than nickles and seven fewer quarters than dimes. How many coins of each type did she receive? Penny Nom lui répond. 





Fourth and fifth degree polynomials 
20090820 

Evin pose la question : hello.i am a student . ax^4+bx^3+cx^2+dx+e=0 x=? i want to learn the solution or formula of equations of the fourth and fifth degree...PLEASE Robert Dawson lui répond. 





Nickels, dimes and quarters 
20090525 

Amy pose la question : Coming from South Africa I find working with nickels, dimes and quarters confusing.
How many dimes are in a nickel and how many quarters are in a dime? Penny Nom lui répond. 





The sum of the roots of a quartic 
20090421 

dave pose la question : This is a algebra problem that i am confused about:
The sum of the roots of x^4x^3+5x^2+4=0 is:
i tried graphing it, but it shows that there are no roots, but the answer is 1. are they wrong? Penny Nom lui répond. 





Fractional part 
20090401 

Galina pose la question : What fractional part of eight is eight hundredths Stephen La Rocque lui répond. 





Partial derivatives 
20090117 

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. 





(a x b) intersect (b x a) 
20090108 

sean pose la question : is it possible to have two sets such that
n((a X b) intersect (b X a) =3 Harley Weston lui répond. 





The sum of the roots of a quartic 
20090103 

peter pose la question : How do you find the roots of an equation without graphing? like, i have a problem that says what is the sum of the roots of x^4x^3+5x^2+4=0. Harley Weston lui répond. 





Partial variation 
20081103 

Diamond pose la question : what are the 2 parts of partial variation? Penny Nom lui répond. 





Nickels, dimes and quarters 
20081027 

val pose la question : I would like help working out a math word problem. A collection of 30 coins worth $5.50 consists of nickels, dimes, and quarters. There are twice as many dimes as nickels. How many quarters. Could you teach me how to find this formula? Penny Nom lui répond. 





Integration 
20081017 

hazela pose la question : integration of
x sinx cosnx Harley Weston lui répond. 





Art and Integers 
20080917 

pamela pose la question : how do artists use integers? Janice Cotcher lui répond. 





Cubic yards and quarts 
20080916 

Mary pose la question : I need 2 yards of soil, how many quarts is this? Penny Nom lui répond. 





A string around the world 
20080818 

Terry pose la question : I heard this on T.V. and was wondering if it was true. Place a string around
the world, you would need 25,000 miles of string. If you raised the string
off of the ground by 1 foot all the way around. How much more string
would you need? Penny Nom lui répond. 





The weight of a cubic yard of dirt 
20080721 

Robert pose la question : I need to know how many pounds of dirt is in a cubic yard Penny Nom lui répond. 





How far away is the horizon? 
20080613 

Ali pose la question : A plane is 10km above the earths surface, and you want to know how far away the horizon is, you know that the radius of the earth is about 6400km, how far away is the horizon along the earth's curved surface. My teacher has drawn a diagram; a circle representing the earth with one vertex at the center of the earth, another vertex outside the cirlce representing the plane (the distance between the earth and plane is 10km) and the last one is on the circle representing the horizon. Could you please explain how I would solve this problem, thanks! Penny Nom lui répond. 





Throwing a ball on the moon 
20080521 

leria pose la question : equation for motion of moon is h=2.67t^2 + vt + s
equation for earth h=16t + vt + s
Suppose you are on an outpost on the moon and Jan is back on Earth. Both people toss a ball from a height of 96 feet with an initial velocity of 16 feet per second. How much longer will your ball stay in motion on the moon than Jan's on the earth?
Math Central,
I'm having a difficult time understanding which numbers to plug into the formula. Stephen La Rocque lui répond. 





The wedges in a circle graph 
20080518 

Libby pose la question : I don't understand how to do this word problem:
The cafeteria workers distributed a survey to the student body asking students to pick 1 from a list of 5 choices for their favorite lunch. The circle graph below gives the results of the survey for the students who responded. What is the measure, in degrees, of the central angle for each choice?
And there is a pie chart that has food choices with these percentages: 25%, 20%, 15%, 10%, and 30% Leeanne Boehm and Penny Nom lui répond. 





Distance seen 
20080318 

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. 





Integration by parts 
20080130 

seth pose la question : hi i really dont understand integr
ation by parts. for example, the integral(t^2sintdt. i have u=t^2 and v'=sint also u'=t^/3 v=cost
for the formula i have uvintegralvu' dx this is all well and good but i cant get it right. Harley Weston lui répond. 





A large concrete shape 
20080116 

Keith pose la question : what is the cubic yards of an area that is not a perfect 1/4 circle?
The dimensions are 100ft. x 60ft. x 125ft. curcumferal arch x 3ft. depth? Stephen La Rocque lui répond. 





Partial fractions 
20080106 

taiwo pose la question : i copied the question below from john bird's higher engineering mathematics
fourth edition (pg 19) after solving all the partial fraction questions from the book
except this:
x^3 + 4^2 + 20x  7 over (x1)^2 (x^+8). i will appreciate it if you help me out so i can
know whether their answer is correct. thanks alot Harley Weston lui répond. 





Partitioning a clock face 
20071219 

Kim pose la question : Using a clock with a regular circular faced dial, draw two straight lines such that the sum
of the numbers in each of the three areas is equal. The team at Math Central lui répond. 





Pictographs 
20071211 

eniyah pose la question : The title of my pictograph is Favorite pets. I have two columns. in my first column is the kind of pet and the second column is the numbers of students, the dogs have 16 student that like them and cats have ten students the likes them. each pictures equals 2 stodents my question is. i have to draw paictures to show the number of students for each row. the key says each symbol equals 2 students. since 16 divided by 2 is 8 can you show me how to make this in a graph Stephen La Rocque lui répond. 





Dividing a circle 
20071123 

matt pose la question : hi. can you please send me a diagram of how to draw 3 lines in a circle to get 8 sections. Stephen La Rocque lui répond. 





Motion along a line 
20071002 

Claudette pose la question : If the position function of a particle is x(t) = sin^2(2t), find the distance that the particle travels from t = 0 to t = 2 Harley Weston lui répond. 





Three circles 
20070929 

Kevin pose la question : 3 given circles of R80, R56 & R24 are all in contact. The 2 smaller ones are inscribed in the big one.
Find by calculation or graphically (both if possible) the radiusof a 3rd circle which will be in contact with all 3 given circles. Chris Fisher lui répond. 





A place value chart 
20070912 

glenwood pose la question : draw a million chart then place the following numbers in the proper place.
one hundred and nine million, seven hundred and twentythree Penny Nom lui répond. 





A problem concerning the medians of a triangle 
20070801 

leeja pose la question : In a triangle ABC the sides BC and AC are given. It is also known that
the medians to these sides are perpendicular to each other. Calculate the
length of AB in terms of the other two given sides. Chris Fisher lui répond. 





Simplifying a quartic rational expression using long division 
20070614 

Megan pose la question : x+2/12x^4+17x^3+0x^2+8x40= Stephen La Rocque and Penny Nom lui répond. 





Who was the mathematician that united algebra and geometry? 
20070508 

Victor pose la question : who was the mathematician that united algebra and geometry Penny Nom lui répond. 





How many yards of soil is 55 quarts? 
20070320 

Claudette pose la question : Costco sells bags of dirt in the quantity "55 quarts".. This makes no sense to me.
How many yards of soil is 55 quarts?
Thanks! Stephen La Rocque lui répond. 





Nickels, dimes and quarters 
20070318 

Alexandra pose la question : Ellen has two more nickels than dimes and three more quarters than nickels. She has $3.35 in all. How many coins of each type does she have? Penny Nom lui répond. 





Nickels, dimes and quarters 
20070205 

Avinash pose la question : Mary has 48 coins made up of nickels, dimes and quarters with a total value of $5.10. She has 4 more dimes than nickels and quarters combined. How many coins of each kind does she have? Use matrix to solve the system Stephen La Rocque lui répond. 





Integration 
20070202 

Jenna pose la question : How do I integrate ( ln(x) ) / ( x^2 ) ? Penny Nom and Claude Tardif lui répond. 





Upper Quartiles 
20070126 

Jamie pose la question : I see you have a question about Q3 with even numbers but what about odd numbers? I have a problem with 19 numbers 36,45,49,53,55,56,59,61,62,65,67,70,75,81,82,86,89,94,99. Is there anyway the answer could be 81.5 because every time I do it I get 82 and my teacher tells me that is wrong. So in conclusion how do you do it? Penny Nom lui répond. 





Word problem 
20061022 

Sabrina pose la question : Thomas bought a badminton racquet and paid for it in quarters. If Thomas had used nickels and dimes, he would have needed 20 more dimes than quarters and one more than twice as many nickels as quarters. How much much did the badminton racquet cost? Stephen La Rocque lui répond. 





Plotting coordinates on a number plane 
20060908 

Victor pose la question : I need to plot coordinates (0,2), (2,2), (2,0), and (0,0) on a number or coordinates plane, I am not sure how to do this, and get lost after the first point, can you please help? Penny Nom lui répond. 





Designing a garage 
20060608 

A builder pose la question : I'm currently designing a garage and came upon this interesting math problem. I've tried using various methods to solve it but have so far been unsuccessful. I've included a picture as its far easier to show you my question than explain it verbally. I realize it could be done by trial and error but i'm looking for a real solution. Stephen La Rocque and Penny Nom lui répond. 





The distance to the moon from earth 
20060519 

Maira pose la question : Using trigonometric functions first, show how to find the distance to the moon from earth and then find the radius of the moon. Stephen La Rocque lui répond. 





A triangle problem 
20060518 

Jim pose la question : Right angle triangle with a hypotenuse of 20 units.
Square inside the triangle with sides of 4 units, the square shares two sides with both legs of the triangle, and the corner touches the hypotenuse limiting the triangles size. Penny Nom lui répond. 





Can one divide a circle into 4.5 parts 
20060330 

Chris pose la question : If it is possible, can one divide a circle into say, 4.5 parts (with 4 equal parts and a half part)?
Or for that matter, for any integer, n, into n/2 parts as above?] Walter Whiteley lui répond. 





How far from Earth is Neptune? 
20060321 

Scott pose la question : A laser beam travelling at the speed of light bounces off the planet Neptune and returns to Earth in 29 960.72 s. The speed of light is 299 792.5 km/s. How far from Earth is Neptune? Penny lui répond. 





Quarts, liters cubic yards and soil 
20060319 

Kathy pose la question : I am trying to find out how many quarts of dirt there are in a yard of dirt. The local flower store sells bags of dirt that are 20 quarts or 22 liters for $1.25 and another store sells a yard of dirt for $25.00. Which is the better deal? Penny Nom lui répond. 





What names are known for the quarter circle shape? 
20060306 

Christina pose la question : What names are known for the quarter circle shape? Stephen La Rocque and Penny Nom lui répond. 





Outliers in a box and whisker plot 
20060219 

A student pose la question : i need help on determining if their is an outlier...i know how to find the median and the lower quartile and the upper quartile..but i don't understand about the outliers....please tell me if their is an outlier in this problem....the numbers are...63,88,89,89,95,98,99,99,100,100 Penny Nom lui répond. 





Polar to Cartesian coordinates 
20060115 

Linden pose la question : How do you convert six units at 30 degrees Polar Coordinate into a Cartesian Coordinate? Penny Nom lui répond. 





A sheet metal cone 
20051205 

Laura pose la question : I am an art student and in the process of making a cone out of sheet metal. I am unable to work out the template I need to produce my final cone. The dimensions I have are that the final cone will be 58mm high and will have a diameter of 102mm. Penny Nom lui répond. 





Factoring quartics 
20051113 

Kyle pose la question : How do I factor y^{4} + y^{2} +1?? I think the answer is (y^{2} + y + 1)(y^{2}  y + 1), but I'm not sure how to get that... Chris Fisher lui répond. 





The volume of the earth in gallons 
20050818 

Daniel pose la question : I would like to know how to find the volume of the Earth in gallons. Penny Nom lui répond. 





Proof by induction? 
20050810 

Peter pose la question :
I am a lecturer and am having a problem with the following Proof by
Induction.
If
(N x N x N x N) + (4 x N x N x N) + (3 x N x N) + (N) = 4000
Prove that N is even!
Chris Fisher and Penny Nom lui répond. 





Difference in latitude 
20050405 

Gretel pose la question : Assuming the the earth is a sphere of radius 6378 kilometers, what is the difference in latitude of two cities, one of which is 400 kilometers due north of the other? 500 kilometers? Penny Nom lui répond. 





21yd 2ft divided by 5=what? 
20050310 

A student pose la question : 1gallon 3qt divided by 6= what?
21yd 2ft divided by 5=what? Penny Nom lui répond. 





Perfecting an ideal gambling system 
20050306 

Gaz pose la question : I am a screenwriter, currently in the fortunate position of having the development of a Screenplay funded by the South Australian Film Corporation. The (anti)hero of this screenplay is a statistician whose life is falling apart around him, thanks in part to his obsession with perfecting an "ideal" gambling system. Andrei Volodin lui répond. 





Stewart's Theorem 
20050117 

Amy pose la question : In triangle ABC, AB=4, AC=6 and AD=5, where D is the midpoint of BC. Determine BC. Chris Fisher lui répond. 





Converting coordinates 
20041025 

Allen pose la question : I am trying to help my son with his home, but I don't remember these conversions. Please help.
1. Convert the following coordinates
Cartesian x = 7, y = 24
2. Convert the following coordinates
Polar r = 4, theta = pi / 3 Penny Nom lui répond. 





A partial derivative 
20040319 

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. 





How far can you see? 
20031215 

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. 





The volume of an earthen pit 
20030912 

Bruce pose la question : This shape would occur at the four corners of a rectangular shaped earthen pit with sloping sides (1:1.5). Depth is 14'. Top dimensions are 170' by 158'. After calculating the easy volume components of this shape, we are left with the end corner pieces. 21' base, 14' height, side hypotenuse 25.24' and corner diagonal 32.83'. We're confused. Thank you for any help you may provide. Penny Nom lui répond. 





Integrating e^x sin(x) 
20030503 

Lech pose la question : I am having trouble integrating the following expression by parts: ex sin(x) I used the integrator at http://www.integrals.com/ to find the solution, ? 1/2 ex cos(x) + 1/2 ex sin(x). This is easy to confirm by differentiation, however I am confounded as how to arrive at the answer. Penny Nom and Claude Tardif lui répond. 





Hidden by the curvature of the Earth 
20030423 

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. 





Two intersecting graphs 
20030423 

Patty pose la question :
a) graph the equation x^{2}  y  4 = 0
x^{2} + y^{2} = 9 on the same set of coordinate axes. I did not have a problem with this. The problem is part (b) of the question ask: Find all solutions of the system in part (a) algebraically. Express answers in decimal form, accurate to two decimal places. Penny Nom lui répond. 





Wrap a rope around the equator 
20030212 

Ali pose la question : If you take a rope and wrap it around the equator and then overlap it 6ft. and cut off the extra then you loosen it up so the ends meet how far would it stand off the ground? Penny Nom lui répond. 





A penny, a nickel, a dime, a quarter, and a loonie 
20030121 

Blaine pose la question : I have 5 coins: a penny, a nickel, a dime, a quarter, and a loonie. How many different amounts of money could I pay using any combination of these coins? Penny Nom lui répond. 





Two problems 
20021014 

Eva pose la question :
a) How many different equivalence relations can be defined on the set X={a,b,c,d}? b)Show that 6 divides the product of any 3 consecutive integers. I know it is true that 6 divides the product of any 3 consecutive integers. However, i have problem showing the proof. Leeanne Boehm and Penny Nom lui répond. 





The entire earths' population would fit in the state of Texas 
20020918 

Roz pose la question : I have been told that the entire earths' population would fit in the state of Texas and each person would have 1/2 acre. Is this true. Chris Fisher lui répond. 





Ratios and weights on Neptune 
20020603 

Janice pose la question : The ratio of an object's weight on earth to it's weight on Neptune is 5:7. How much would a person who weighs 150 pounds on earth weigh on Neptune. Penny Nom lui répond. 





Nickles, dimes, quarters and fifty cent pieces 
20020108 

A parent pose la question : The total for all coins counted is $4,564.50 The last coin added to the pile is a 50 cent piece There are 8 times as many 50 cent pieces as there are quarters There are 6 times as many dimes as nickles How many of each are there? Penny Nom lui répond. 





2/3 vs 3/4 
20020102 

Julia pose la question : So, here's my question. Some of the problems they've had to do starts off with two fractions, and they have to tell whether the two fractions are:  The first one is greater than the second one
 The first one is less than the second one, or
 They are equal.
One day my son had the problem of 2/3 vs 3/4. Without drawing out a pie chart, how in the world can a child "eyeball" a problem like this and tell what the correct answer is? I've also tried to teach about making common denominators, but that's going over his head at this point. Denis Hanson and Harley Weston lui répond. 





Box and Whisker plots 
20011119 

Rod pose la question : In our Prealgebra course, we have been studying Box and Whisker plots. Recently, we learned how to decide whether a data point is an outlier or not. The book (Math Thematics, McDougall Littell) gave a process by which we find the interquartile range, then multiply by 1.5. We add this number to the upper quartile, and any points above this are considered to be outliers. We also subtract the number from the lower quartile for the same effect. My question: where does this 1.5 originate? Is this the standard for locating outliers, or can we choose any number (that seems reasonable, like 2 or 1.8 for example) to multiply with the Interquartile range? If it is a standard, were outliers simply defined via this process, or did statisticians use empirical evidence to suggest that 1.5 is somehow optimal for deciding whether data points are valid or not? Penny Nom lui répond. 





A 3 dimensional 5 pointed star 
20011108 

Kent pose la question : I am looking for a formula that will give me a layout for a 3 dimensional 5 pointed star. I want to form it out of sheet metal, using 5 polygons and soldering them at the apex. Can you please help me with this? I would like to be able to give the formula the height of the star from the bottom two points to the top point and also how deep the star is. Thank you very much! Judi McDonald lui répond. 





Dividing a circle 
20011017 

Ahmeen pose la question : I am having a hard time figuring out how a circle can be divided into 11 equal parts with only 4 cut allowed? My teacher gave this to us and I still can't cut my pie into eleven equal parts with only four cuts. Walter Whiteley lui répond. 





When will the ship disappear? 
20011010 

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. 





The 100 chart 
20010928 

Nich pose la question : Am I suppose to use the 100 chart for these questions. Question One: I am a 2 digit number my tens digit is 2 more than my one digit my 1 digit is between 4 & 6. What # am I ? Question Two: I am a 2 digit # I am greater than 40 but less than 60 my tens and ones digits are the same I am a odd number what am I ? Penny Nom lui répond. 





Counterclockwise 
20010914 

Rolanda pose la question : When Descartes invented the coordinate system he decided to number them counterclockwise. Why? Chris Fisher lui répond. 





Earthquake warning 
20010903 

Dillon pose la question : In the city of Skangai there are 6 million people.Each person has to tell 2 more people that theres going to be an earthquake. After they do they leave the city. There will be no duplications.It takes 3 minutes to tell each person. How long will it take for the whole city to know about the earthquake? Penny Nom lui répond. 





Integration by parts 
20010409 

A student pose la question : how do you integrate x tan^{1}x dx, i know it can be done by integration by parts maybe, but i'm not sure.... Claude Tardif and Harley Weston lui répond. 





Two integrals 
20010403 

Jim pose la question : I'm having trouble with these integrals. Can you help me out? 1)the integral of:
x^{5} arctan x dx 2)the integral of:
2x^{5} + 9x^{4} + 19x^{3} + 13x^{2}  5x  25  dx x^{4} + 4x^{3} + 5x^{2} Claude Tardif lui répond. 





A quartic equation 
20010215 

George pose la question : Let P(x) = x^{4} + ax^{3} + bx^{2} + cx + d. The graph of y = P(x) is symmetric with respect to the yaxis, has a relative max. at (0,1) and has an absolute min. at (q, 3) a) determine the values for a, b c, and d using these values, write an equation for P(x) b) find all possible values for q. Harley Weston lui répond. 





Part of a part 
20010211 

Katie pose la question : Hello! I was looking at your Fraction questions and since i am pursuing to be an elementry school teacher i feel i don't understand one of your responses. How would you explain this to an elem, midd, and high school student. Even me myselfin college really does not understand. The question was: When you multiply two positive fractions less than 1, how does the answer compare to the size of the fraction? Why? Penny Nom lui répond. 





Place value chart 
20010111 

Charles pose la question : Can you send me a pictorial example of a place value chart? Harley Weston lui répond. 





A dollar, quarter, dime, nickle and penny 
20010107 

Sarah pose la question : Arnold has a dollar coin, one dime, one quarter, one nickel, and a penny. The number of different sums of money that can be formed using three coins is... Penny Nom lui répond. 





A quartercircle and two semicircles 
20001231 

Christopher pose la question : Inside the quartercircle are two semicircles with the same radius, (r). Which has a greater area, G or L? Penny Nom lui répond. 





A cycloid in Cartesian form 
20000920 

Billy pose la question : The parametric equation of cycloid is given: x=r(tsint) y=r(1cost) How to eliminate t? Harley Weston lui répond. 





Buying art supplies 
20000918 

Travis pose la question : An art teacher buys exactly 100 items at this sale, and the total cost before tax is $100. She buys at least one of each item. How many of each item does she buy? Markers $0.50 Sketch Pads $3.00 Paint Sets $10.00 Denis Hanson lui répond. 





Uniting algebra and geometry 
20000416 

Beth pose la question : Who is the mathmatician that united algebra and geometry??? Claude Tardif lui répond. 





All the roots of x^6  64 
20000415 

Dakota pose la question : Find ALL zeros of P(x) = x^{ 6}  64 Walter Whiteley lui répond. 





Congruent parts of congruent figures 
20000310 

Erica pose la question : Yesterday, I recieved a test problem asking to prove two line segments equal. Here is the problem as I was given it: Given: paralleogram ABCD AE is perpendicular to DB CF is perpendicular to DB Prove: AE is equal to CF I answered the problem as follows: . . . Walter Whiteley lui répond. 





Party favors 
20000222 

Krystina Fernandez pose la question : Luanne was making party favors for her little sister's birthday party. Each party favor was in the shape of a cube. Luanne had pink and purple paint to paint the cubes and she could paint each face only solid pink or solid purple (no dots,stripes,ect.).For example, one cube may be all purple, another may have two purple faces and four pink faces. Her little sister wanted to have a different cube for each guest.(A cube is not considered different if it can be turned so that all it's sides match the corresponding sides of another cube.)How many different cubes was it possible for Luanne to make? Claude Tardif lui répond. 





A valentines project 
20000221 

Courtney Dohoney pose la question : I was assigned a valentines project. Our job is to make a valentines card that has a math theme. On my valentines card I would like to include the set of equations that when graphed look like a heart. If you can figure out a set of equations and get it back to me I would be very happy. Harley Weston lui répond. 





Mass of the earth 
20000221 

Terry Broughton pose la question : My name is terry i am 15 my question is how much does our planet earth weigh ? Chris Fisher and Harley Weston lui répond. 





How wide is the well? 
19991124 

Chris Baranski pose la question : There is a well and in the well there are 2 sticks one is 2 meters long the other is 3 meters long and they are opposite to each other. They are leaning against the wall of the well. The place where they touch is 1 meter of the bottom of the well. How wide is the well? Chris Fisher lui répond. 





Rolling Circles 
19990912 

Craig Ellis pose la question : We have a circle of radius 3. inside the circle and tangent to the circle of radius 3 at one point is a circleof radius 1. The question is if we could roll the smaller circle around the inside of the larger circle how many revolutions would it take to get around to where we started. Chris Fisher and Walter Whiteley lui répond. 





A ladder problem 
19990422 

Michael Blade pose la question : There is a cube box 3feet x 3feet x 3ft resting against a vertical wall on level ground. Resting against the outside corner of the box is a ladder 10 feet tall, this ladder is of course resting on the ground but also against the outside corner of the box and rests on the wall. The question the ladder is divided into two unequal section bounded by the box to the ground and the box to the wall. what are those dimensions? Penny Nom lui répond. 





Calculus problems 
19980713 

Lorraine pose la question : I'm stuck again. Can you help? This involves integration using the method of partial fractions the integral of: 7x(to the 5th)  2x(cubed) + 3 dx  x(to the fourth)  81 Do I have to do long division to reduce the numerator to the fourth power? the integral of: 4 16x +21x(squared) + 6x(cubed)  3x(fourth) dx  x(cubed)(x  2)(squared) Lorraine Harley Weston lui répond. 





Curvature of the Earth 
19980316 

Robert Dyck pose la question : How can I find the curvature per mile of the earths surface? What is it? Harley Weston lui répond. 





The Earth's Arc 
19980206 

Robert Dyck pose la question : How do I find the arc/mile of the earths surface? What is the arc? Harley Weston lui répond. 





Cos(x) Cos(2x) Cos(4x)=1/8 
19970924 

Tan Wang pose la question : How many distinct acute angles x are there for which cosx cos2x cos4x=1/8? Chris Fisher Harley Weston and Haragauri Gupta lui répond. 

