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cosine

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96 articles trouvés pour ce sujet.
 
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probleme sin cos 2006-02-19
Thibault pose la question :
mon probleme commence par: f(x)=sinx (sinx+1)+ cos²x
donc en le dévellopant on trouve: f(x)= sin²x + sinx + cos²x
et apres ce que je ne comprend pas est que par la suite on trouve: f(x)= 1+sinx
qu'est-ce qui fait que l'on trouve ce resultat??

Claude Tardif lui répond.
Solve the equation completely cos 2x = 1 2017-06-08
Lava pose la question :
Solve the equation completely cos 2x = 1
Penny Nom lui répond.
How far apart are the boats? 2016-12-13
Halley pose la question :
Two boats leave port at the same time. Boat A travels east at a speed of 12 km/hr. Boat B travels southwest at a speed of 14 km/hr. After two hours, how far apart are the boats? North is 0 degrees. How do I figure this out. Thanks
Penny Nom lui répond.
Two airplanes 2015-04-14
john pose la question :
two planes leave an airport at the same time, one going northwest (N35*W)at 400 mph and the other going east at 332 mph. How far apart are the planes after 4 hours to the nearest mile?
Penny Nom lui répond.
Trig functions and the unit circle 2014-10-02
Jake pose la question :
I was wondering what conclusions can be drawn about the trigonometric functions and how they work about the circle. Can you also please give me an explanation for it? Thank you.
Penny Nom lui répond.
A triangular chicken pen 2014-04-27
Cierra pose la question :
Margaret has two lengths of fence, 20 meters and 24 meters, for two sides of a triangular chicken pen. The third side will be on the north side of the barn. One fence length makes a 75° angle with the barn. How many different pens can she build if one fence is attached at the corner of the barn? What are all the possible lengths for the barn side of the pen?

Not sure what they are asking here... please show step by step what to do! Thank you so much!

Penny Nom lui répond.
The sides of a triangle 2014-04-06
Michael pose la question :
I am supposed to sove for the length of side "b" of an irregular triangle. I am given the following:
Side a: 65'
Side b: Find this length
Side c: 50'
Angle A: unknown
Angle B: unknown
Angle C: 52 degrees
I am supposed to use the law of cosines to solve for side "b" and my teacher says there is no mistake in the "givens" for the problem. I do not see how this can be done using the law of cosines and i have not figured out how to sove for angle B to use the law of cosines.

Penny Nom lui répond.
A triangle problem 2013-10-02
raneem pose la question :
ABC is a triangle in which : BC=20cm. M(<B) =29 and m(<C)=73 . D is the midpoint of BC Find the length Of AB and AD approximated to 2 decimal places
Penny Nom lui répond.
We can't write sinx and cosx as a finite polynomial. 2013-03-31
rimoshika pose la question :
prove that we can't write sinx and cosx as a finite polynomial.
Walter Whiteley lui répond.
The fourth side of an irregular polygon 2013-02-01
Emran pose la question :
I have a irregular polygon. I know 3 of the 4 sides, and 2 of the angles. A-B is 285, B-C is 149, and C-D is 310. Angle B is 135 degrees. and Angle C is 45 degrees. Is there a formula to solve for the final side? Thanks.
Penny Nom lui répond.
cos(theta/30) = 1 2012-05-14
Hope pose la question :
cos (theta / 30 = 1
I am very confused as to how to solve it. Can you help?

Penny Nom lui répond.
Tangent of theta 2012-01-17
stahl pose la question :
explain what the 'tangent of theta' means. Draw and label a diagram to help with your explanation.
Harley Weston lui répond.
Three sides of a triangle 2011-12-24
saba pose la question :
the three sides of a triangular lot have lengths 10,11and 13cm,respectively. find the measure of its largest angle and the area of the lot?
Penny Nom lui répond.
How far must the pitcher travel to get to the ball? 2010-11-04
ken pose la question :
A baseball player bunts a ball down the first base line. It rolls 35ft at an angle of 26 degrees with the first base path. The pitchers mound is 60.5 ft from the plate. How far must he travel to get to the ball.
Penny Nom lui répond.
A radio tower 2010-03-26
Alex pose la question :
The height of a radio tower is 450 feet, and the ground on one side of the tower slopes upward at an angle of 10 degrees. How long should a guy wire be if it is to connect to the top of the tower and be secured at a point on the sloped side 110 feet from the base of the tower?
Harley Weston lui répond.
A quadrilateral with 4 known sides and 1 known angle 2010-03-19
samuel pose la question :
Name: Samuel
Status: Student

I have a quadrilateral with 4 known sides and 1 known angle, and I'm trying to evaluate the other angles of my quadrilateral.

By the law of cosines, I can easily find my opposite angle (using the diagonal as a basis for the equation).

However, to find the two remaining angles, I have found no other way so far than to use the other diagonal, which can be found with the equation attached (from geometry atlas).

Is there any simpler way?

Robert Dawson and Harley Weston lui répond.
Solving a triangle 2010-01-25
Paige pose la question :
how do i solve a triangle with one angle of 73 degrees, one angle of 32 degrees, and one side of 23cm?
Harley Weston lui répond.
A trig question 2009-12-15
A trig question pose la question :
Hey, my name is Candle
I'm in academic math10 and am stuck on my trig... one question I thought I had right because i used the cosine law I got wrong and can't figure out why... here's a copy of the question. (i guessed it was D... but my teacher said it's B)
Thanks
Candle

Robert Dawson lui répond.
How fast is the distance between the two cars decreasing? 2009-12-08
Jenny pose la question :
Two cares are on a collision course toward point P. The paths of the two cars make a 30 degree angle with each other. The first car is 40 km from P, and traveling toward P at 16 km/hour. The second car is 50 km from P, traveling at 20 km/hour. How fast is the (straight line) distance between the two cars decreasing. (Hint: Law of Cosines)
Harley Weston lui répond.
Vectors and the Law of Cosine 2009-06-08
lauren pose la question :
once force of 20 pounds and one force of 15 pounds act on a body at the same point so that the resultant force is 19 pounds. Find, to the nearest degree, the angle between the two original forces
Janice Cotcher lui répond.
Related rates 2009-03-09
Megan pose la question :
A plane flying with a constant speed of 330 km/h passes over a ground radar station at an altitude of 3 km and climbs at an angle of 30°. At what rate is the distance from the plane to the radar station increasing a minute later?
Harley Weston lui répond.
Find the resultant of this displacement pair 2009-02-22
katydidit pose la question :
Find the resultant of this displacement pair:
500 miles at 75 degrees east of north and 1500 miles at 20 degrees west of south.
How do I graph this and how do I solve this problem?

Penny Nom lui répond.
The angle between two lines 2008-12-17
abhi pose la question :
how to calculate the angle between two lines, given the length of the lines.. angle should vary from 0 - 360 in the counterclockwise direction
Robert Dawson and Harley Weston lui répond.
The path of a small sailboat 2008-11-19
jane pose la question :
a sailor in a small sailboat encounters shifting winds. she sails 2.00 km East then 3.40 km North East, then an additional distance in an unknown direction. Her final position is 6.68 km directly east of the starting point. find the magnitude & direction of the third leg of the voyage.
Harley Weston lui répond.
How far are the boats apart? 2008-11-14
dom pose la question :
Two boats leave port at the same time. They leave at 150 degree angle. One boat travels at 10mph and the other at 20mph. After two hours how far are the boats apart?
Penny Nom lui répond.
The angles and sides of a triangle 2008-11-13
JAMIE pose la question :
a triangle with a side(b)37m an angle(C)70degrees and (a)79m find values of angles A and B and length of side c
Stephen La Rocque lui répond.
Radii and Chords Create a Non-Right Triangle 2008-08-22
Beary pose la question :
AOC is a diameter of circle O. Line AB is 12, and lines OA and OC (the radii) are 10. Find the length of line BO and chord BC.
Janice Cotcher lui répond.
Arc-length and sector-angle 2008-08-06
Benson pose la question :
If chord length, radius are given, How to find the sector angle and arc-length
Janice Cotcher lui répond.
Guy wires for a tower 2008-05-19
larissa pose la question :
a radio tower 500 feet high is located on the side of a hill ( the hill has an inclination to the horizontal of 5 degrees.) How long should two guy wires be if they are connected to the top of the tower and are secured at two points 100 feet directly above ( up the hill ) and directly below the base of the tower?
Penny Nom lui répond.
The length of the third side of a triangle 2008-02-16
mary pose la question :
I have an angle of 72 degrees and each of the sides are 5' long. What is the distance from each of the ends of the 5 feet to form a triangle.
Stephen La Rocque lui répond.
The cosine of an angle 2008-01-21
Kristine pose la question :
Find measure of unknown side cosA=0.5
Harley Weston lui répond.
The angles of a triangle given the three sides 2008-01-17
Lucy pose la question :
Is there a way to find the angles of a triangle just by knowing the lengths of it's sides? It seems like the would be a relationship between the two, but I'm not sure.
Stephen La Rocque and Harley Weston lui répond.
How far is the jet from the lighthouse? 2008-01-07
Natalie pose la question :
Question: A ship spots a lighthouse that is 53m high, at an angle of elevation of 7 degrees that is directly north of the ship. The same ship spots a jet travelling N62E at an altitude of 1500m with an angle of elevation of 15 degrees. How far is the jet from the lighthouse?

Natalie

Harley Weston lui répond.
The definition of the sine function 2007-11-22
Indrajit pose la question :
I need a explanation in this theory.......if sinθ = p/h...then
sin 90 deg. = p/h
or 1 = p/h
or p=h .....how can a perpendicular be equal to a hypotenuse.???

Harley Weston lui répond.
Area of a quadrilateral 2007-10-10
Courtney pose la question :
how would i find the area of a quadrilateral..
the sides are a (/) is 6cm, b (—) is 9 cm, and c (\) is 7 cm..
the angle between a and b is 140 degrees and b and c is 115 degrees..

Stephen La Rocque lui répond.
The length of the third side of a triangle 2007-08-15
Brooklyn pose la question :
What is the equation to find the length of the third side of a triangle if you have the length of A, B, and the angles(s)?
Stephen La Rocque lui répond.
Calculating the area (acreage) of a four sided lot 2007-07-18
A property owner pose la question :
I have a real estate property and the lot size is something I need to find out. I know the lengths of the four sides, but it isn't a rectangle, it is an odd shape. How do I find the acreage?
Stephen La Rocque lui répond.
Trig functions for angles not between 0 and 90 degrees 2007-07-16
Tim pose la question :
My question: Why is the value of a trigonometric function, the same, for an angle over 90 degrees and its reference angle? How are the angle and its reference related? Do they both form a triangle that has equal sides?
Penny Nom lui répond.
Any regular polygon inscribed in a circle 2007-07-12
DJ pose la question :
Circle with r=12" is inscribed in a regular octagon. What is the length of each octagon segment? Note: Our answer works for any regular polygon inscribed in any circle.
Stephen La Rocque lui répond.
sin|x| and cos|x| 2007-06-25
Mac pose la question :
Can anyone tell me whether sin|x| and cos|x| is differentiable at x=0 ? As far as i know, cos(x) and sin(x) is differentiable at all x.
Penny Nom and Stephen La Rocque lui répond.
The area of a quadrilateral 2007-06-10
Lucy pose la question :
Calculate the area of the quadrilateral ABCD. AB= 4.1cm, BC = 7.6cm, AD= 5.4 cm, CD= ? Angle ABC = 117, Angle ADC = 62. Give your answer correct to 3 significant figures.
Stephen La Rocque and Penny Nom lui répond.
Evaluating sine and cosine 2007-05-06
Selimovic pose la question :
How can i solve sine or cosine for angle of, lets say 10°....Maybe it's easy but i don't know how...
Penny Nom lui répond.
The law of cosines 2007-03-23
chetna pose la question :
Q 1) In triangle LMN, l=7, m=5 , n=4. find ANGLE N. After applying the rule and substituting values i'm getting Cos n= 58/40. Is there something wrong. The answer at the back of the book is 34 degrees.
Penny Nom lui répond.
A curve on a cylinder 2007-01-27
John pose la question :
think of a tube,say 50mm in diameter made out of cardboard, project vertical lines at right angles from the base at say every 2mm right round the tube in pencil.No pretend you can put this cardboard tube in a saw and cut it at 45degrees. Get a pair of scissors and cut it at the lowest end and lay it out flat.It now looks like a graph,how do you work out each of these vertical lengths possibly chord lengths
Stephen La Rocque and Penny Nom lui répond.
lim x-->infinity cos x 2006-12-07
Katie pose la question :
I was wondering if it was possible to find: lim x-->infinity cos x
Stephen La Rocque lui répond.
cos2x=1 2006-11-21
Christina pose la question :
I'm have a hard time solving cos2x=1 for exact values between 0<_x <360
Stephen La Rocque and Penny Nom lui répond.
A trig problem 2006-06-24
Greg pose la question :
A and B are two towers, B being 4 km due east of A. The true bearings of a flagpole, C, from A and B are α east of north and α west of north respectively. The true bearings of a second flagpole, D, from A and B are (α + β) east of north and (α - β) west of north respectively. Assuming A, B, C, and D are on level ground, and that α = 25, β = 10, find the distance between C and D.
Penny Nom lui répond.
The chord length of a polygon 2006-06-14
Krishna pose la question :
I have to find out the chord length of a polygon - Tetradecagon ! The Radius of the Circle is 11.5 Cms. The Circle is intersepted by 14 arcs. Then how to find out the chord length?
Stephen La Rocque lui répond.
The interior angles of a right triangle 2006-05-20
Greg pose la question :
I am wondering if there is a way to figure out the interior angles of a right triangle if we know ONLY the side lengths, and the trick is, we CANNOT use arctangent!
Leeanne Boehm and Penny Nom lui répond.
Solve the equation cos x = sin 20 where x is acute. 2006-03-26
Elle pose la question :
Solve the equation cos x = sin 20 where x is acute.
Stephen La Rocque lui répond.
Three towns are located at the vertices of an equilateral triangle 2006-03-20
A student pose la question :
three towns are located at the vertices of an equilateral triangle. The towns are 8, 5, and 3 miles, respectively, from a store. How far apart are the towns?
Chris Fisher lui répond.
How do you find the angles in a triangle? 2006-01-27
Keith pose la question :
How do you find the angles in a triangle if you know the lengths of the sides?
Chris Fisher and Penny Nom lui répond.
The period of sin(x) + cos(x) 2005-07-21
A student pose la question :
WHAT IS THE PERIOD OF SIN(X)+COS(X)?
Penny Nom lui répond.
The tide at a boat dock 2005-01-11
Abraham pose la question :
The tide at a boat dock can be modeled by the equation

y = -2cos(pi/6 t) + 8,

where t is the number of hours past noon and y is the height of the tide, in feet. For how many hours between t=0 and t=12 is the tide at least 7 feet?

Penny Nom lui répond.
Modelling monthly temperature with a cosine 2004-12-25
Regis pose la question :
The average monthly temperature for a location in Ontario as a function of month number can be modelled using the equation y = a cos[k(t + b)] + d.
Harley Weston lui répond.
Solving triangles 2004-10-30
Allen pose la question :
Solve the following triangles.

Given

1. B = 20 Degrees, a = 25, b = 16
2. A = 35 Degrees, b = 2, c = 3
3. A = 32 Degrees, C = 44, c = 20

Harley Weston lui répond.
Finding bearings 2004-05-24
James pose la question :
This question is about finding bearings. A boat race starts from point A, goes North to Point B, a distance of 1000 meters. The course is triangular. The bearing from point B to point C is South 70degrees West. The distance from Point B to point C is 1500 meters. Find the course bearing from C to A.
Penny Nom lui répond.
Cosine of 35 degrees 2004-03-03
Jason pose la question :
How do you find the exact solution to cosine 35 degrees.
Chris Fisher lui répond.
Sin(3x), cos(3x) and tan(3x) 2004-01-28
Jon pose la question :
What is the identity for cos3x, sin3x, and tan3x? In class, we learned double angel identities and were asked to find out the identity to these three trig functions. If you can help, please do. Also, i know that the cos4x- sin4x is the same as cos2x. Is cos8x-sin8x = cos2x also true? Thank you.s
Chris Fisher lui répond.
Laws of sines and cosines 2003-11-23
A parent pose la question :
On the one side of a stream lines PA= 586.3 feet, PB = 751.6 feet are measures, angle APB being 167 degrees and 36 min. Q is a point on the opposite side of the stream. Angle PAQ=63 degress and 18 min and PBQ=49 degrees and 24 min. Find PQ.
Penny Nom lui répond.
Odd powers of sine and cosine 2003-06-25
Antonio pose la question :
Can you please tell me how to integrate a trig function involving sine and cosine? I know if the powers of both the sine and cosine are even and nonnegative, then I can make repeated use of the power-reducing formulas. But for the question I have on my hand, the powers of both sine and cosine are odd: ( sin3x + cos7x ) dx.
Harley Weston lui répond.
Two trig problems 2003-06-10
Bett pose la question :

I have this ongoing trouble with trig and solving triangles with laws of cosines and sines!! For example if it asks to solve triangle FGH, given angle G=102.7 , side f=14.2, and h=18.6. Now do I use law of cosines because I don't have the measure of an angle and length of the opposite side??I don't know where to go from here,I am totally confused!!!

I also have a problem with this word problem I have been doing. It asks: An airplane flies 847.5 km at a bearing of 237.3 degrees. How far south and west fo its original position is it? Huh? Please help!


Penny Nom lui répond.
sin theta = 7/8 2003-05-07
Patty pose la question :
If sin0 = 7/8 and 0 is in quadrant 2, find the other five trigonometric functions of 0. (report your answers in radical form)
Penny Nom lui répond.
Write sin(3x) in terms of sin(x) 2003-05-05
A student pose la question :
Write sin 2x in terms of sin x
Penny Nom lui répond.
How far apart are the transmitters? 2002-05-18
Jeff pose la question :
A ship at sea is 70 miles from one transmitter and 130 miles from another. The measurement of the angle between the signals is 130 degrees. How far apart are the transmitters?
Penny Nom lui répond.
The law of cosines and obtuse angles 2002-05-09
Bryant pose la question :
The question that I am pondering is that I need to derive the law of cosines for a case in which angle C is an obtuse angle.
Penny Nom lui répond.
A trigonometric identity 2002-03-22
Debby pose la question :
I am stuck on a problem and wondering if you can help?? It is: Prove the following:
sec2(X)+csc2(X) = sec2(X)csc2(X)

Harley Weston lui répond.
sin 2x = cos 3x 2002-02-25
Allan pose la question :
solve:

sin 2x = cos 3x

Primary question: how do you handle the cos 3x?


Paul Betts and Chris Fisher lui répond.
Adding vectors 2002-01-12
Lena pose la question :
how do you add vectors together?
If you are given the length and angles of both vectors and are asked to add/subtract them, how do you do it? I know you are supposed to do the head to tail method, but whenever i try it i get the wrong answer. I need help setting it up.

example: A is 2.7cm, and 60 degrees, B is 1.6cm and 135 degrees, find the magnitude and amplitude


Penny Nom lui répond.
The tangent function 2002-01-12
Justine pose la question :
if you know that sin45degress = cos45degrees, how do you know that tan45degrees = 1?
Penny Nom lui répond.
A trig identity 2001-07-27
Jeff pose la question :
prove this identity and show steps
tan(x/2+pi/4)=secx+tanx

Harley Weston lui répond.
The speed of the boat 2001-07-12
Sharon pose la question :
A motor boat is travelling in a southeasterly direction in water that is flowing from the south at 2km per hour. Show that the speed of the boat is (6 times the square root of 2) km per hour, given that it can travel at 10km per hour in still water.
Penny Nom lui répond.
The angles in a triangle 2001-05-11
Nikki pose la question :
Find the measure, to the nearest degree, of each angle of a triangle with sides of the given lengths.

26, 35, 40


Penny Nom lui répond.
The unit circle and trigonometry 2001-04-05
Ashley pose la question :
"My teacher wants us to find out what a unit circle is, which I found out, a circle with the radius of 1, but the problem is he wants us to show the relationship between the unit circle and the sine(30,45,60 degrees), cosine(30,45,60 degrees),and tangent ratios(30,45,60 degrees). I need help with this and my teacher will not help us out. Thanks very much ...
Penny Nom lui répond.
The law of cosines in the real world 2001-02-21
Hope pose la question :
Do you have any examles and/or labs that show how the law of cosines is used in the real world?
Harley Weston lui répond.
Law of cosines 2001-02-20
Emily pose la question :
I missed a few days of class and I can't figure out how to solve Law of Cosines problems. I have the notes and formulas but I can't figure out how to do the math involved to answer the problems. I am also getting confused about how to use degrees and seconds in the Law of Sine and Cosine. I can't seem to get the correct answers and I don't really know how to solve them and enter them into my TI 86.
Harley Weston lui répond.
The laws of sines and cosines 2001-01-02
Faydene pose la question :
Can the sine /cosine rule be applied to a right -angle triangle to find a particular solution or are these 'rules' applied only when the triangle is not right angled?
Penny Nom lui répond.
Trig identity crisis 2000-11-29
Rhiannon pose la question :
I have tried many times to find the answer to these problems but I can't I am in grade 12
  1. tan(x)=csc2(x)-cot2(x)
  2. cos(x)/csc(x)-2sin(x)=tan(x)/1-tan(x)
  3. cos(x)[ tan2(x)1-1]/cos2(x)+sin2(x)=sec(x)

Harley Weston lui répond.
Some trigonometry 2000-08-11
Angela pose la question :
I have some PreCal questions. I am a student at the secondary level. I would be very grateful for your help.

Solve the equation for theta (0 <= theta < 2pi).

tan2(theta) = 3 I know sec2(theta) -1 = tan2(theta)

.
.
.
Harley Weston lui répond.

Using the inverse sine function 2000-05-31
Nelson Rothermel pose la question :
This has me completely baffled. I have to use the laws of sine or cosine to find the angles of a triangle when I have 3 sides, so I can't go 180-x-y when I have 2 angles. Now, I have a triangle with values of 3, 7, and 9. Here are the steps I used (A,B,C are angles; a,b,c are opposite sides):

angle A (16.1951 degrees): cos-1*((b2+c2-a2)/(2*b*c))
angle B (40.6011 degrees): sin-1*(b*sin(A)/a)
angle C (56.7962 degrees): sin-1*(c*sin(A)/a)

If you notice, A+B+C does not equal 180. According to the book, A and B are correct, but C is supposed to be 123.2038 degrees. Why doesn't it work???


Harley Weston lui répond.
Solve 2sin 3x-1=0 2000-05-11
Cynthia pose la question :
How would you solve 2sin 3x-1=0? I don't know what to do with the 3.
Penny Nom lui répond.
sin(7pi/12) 2000-05-04
Kristel pose la question :
What is the exact value of sin 7pi/12?
Chris Fisher and Paul Betts lui répond.
Triple angle formula 2000-02-23
Sara pose la question :
Can one derive a triple angle formula for sine and cosine? If so, how?
Chris Fisher lui répond.
A trig identity 2000-02-17
Eric pose la question :

Question:
How do I solve this problem?

 sin3x   cos3x _____ - _____ = 2 sinx cosx 

Chris Fisher lui répond.
Sines & cosine laws 1999-12-10
Pierre Boivin pose la question :
Triangle LMN, angle L=71 degree , LM= 7.2 , MN=8.3 , ln= 5.9

The questiion was to find angle M. Using the cosine law I found the answer to be 44 degree. It is also the book answer. Using the sines law I found the answer to be 42.2 degree. why can't I use the sines law.
Chris Fisher lui répond.

Cos x = -1/2 1999-12-01
Pierre Boivin pose la question :
When I factor[ 2cos (square) - 5cos -3], I get (2cos + 1)(cos - 3). 2cos + 1 = 0, 2cos = -1, cos = -0.5,. Using inv cos on calculator, I get 120 degree related angle.

When I graph I get two values, between 90 and 180 degree and between 180 and 270 degrees. How do I find those two values. How do use 120 degree in relation with the x axis.
Penny Nom lui répond.

A Trigonometry Question 1999-08-28
Diane Simms pose la question :
My question is can the following be factored. I am a teacher who needs the factors to this right away. 2 Sin2X + 2 SinX CosX - 1= 0
Harley Weston lui répond.
From an airport control tower 1999-08-04
Pammy pose la question :
Hi I am a 30 yo mature age student doing my HSC but am having difficulty understanding this, if you can help me.

From an airport control tower, a Cessna bears 023 degrees T and is 27km away. At the same time, a Boeing 767 bears 051 degrees T and is 61km from the tower. Both planes are at the same height.

i) What is the size of angle ATB?

ii) Using the cosine rule to calculate the distance the planes are apart, to nearest kilometre.

I figured out and drew the triangular diagram but can't figure out the rest and which formula to use. sorry about this, thankyou kindly
Harley Weston lui répond.

Sin 4A 1999-06-22
Ryan Cochrane pose la question :
If sinA = 4/5, and A is a first quadrant angle, find sin4A
Harley Weston lui répond.
Cos(x) Cos(2x) Cos(4x)=1/8 1997-09-24
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.
Finding the Mine 1997-06-23
Billy Law pose la question :
Tom is gold prospector. On his last trip out from town, he headed 35 degree South of West to a lake where he had lunch. The lake was 24 km out of Town. He then headed due East for 35 km before Doubling back on bearing of 15 degree South of west for 20 km to reach his mine. By converting to Cartesian coordinate before doing vector additions do the following:

a) Calculate the position of the mine from town in term of a distance and a direction.
...
Harley Weston lui répond.

A problem with arccos. 1997-06-09
Vanessa Chan pose la question :
Prove: arc cos4/5 + arc cos (-5/13) = arc cos (-56/65)
Harley Weston lui répond.
Ajax, Beverley, Canton and Dilltown 1997-03-14
S. Johnson pose la question :
The following towns are placed on a coordinate system. Ajax at (-x,z), Dilltown at (-10,0), Canton at (0,0) and Beverly at (0,10). The roads from Beverly to Canton and from Canton to Dilltown are perpendiculat to each other and are each 10 miles in length. A car traveling at all times at a constant rate, would take 30 minutes to travel straight from Ajax to Canton, 35 minutes to travel from Ajax to Canton via Beverly, and 40 minutes to travel from Ajax to Canton via Dilltown. What is the constant rate of the car, to the nearest tenth of a mile per hour.
Chris Fisher and Harley Weston lui répond.
A trig problem 1996-12-13
S. Johnson pose la question :
sin t + cos t = 1/5. Find ALL exact values of cot t, given the original equation.
Harley Weston lui répond.
Height of a Hotel 1996-11-07
Irene pose la question :
"Irene" is to determine the # of floors in a hotel 500 feet up the street. Irene is on the 10th floor of an office building and can measure the angle of elevation to the top of the hotel, 57 degrees. Her view of the entire building is obstructed. If the street rises at an angle of 8 degrees from the office building to the hotel and the average distance between floors is 11 feet, how many floors are on the hotel?
Penny Nom lui répond.
A trig identity 1996-03-11
Azmat Hussain pose la question :
Is there an easier/another way to prove the trig identity cos(a+b) = cos(a)cos(b)-sin(a)sin(b)?
Penny Nom lui répond.
 
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