Posted by Hannah on Monday, March 29, 2010 at 9:38pm.
Find the exact value of the trigonometric function given that
sin u = 5/13 and cos = 3/5
1) sin(uv)
My teacher said to make two right triangles and then find the missing parts by the pyth theorem.
For the 5/13 triangle I got 12 and the other triangle I got 4. I do not know what to do now.

Math  Reiny, Monday, March 29, 2010 at 10:41pm
so the angle u could be in quadrant I inside a 5:12:13 triangle, with 13 as the hypotenuse,
so cos u = 12/13
angle v could be in quadrants II or III and are inside the 3:4:5 triangle , with 5 the hypotenuse, so
sin v = 4/5
draw the triangle in quadrant II with those dimensions
You must by now have learned that
sin(AB) = sinAcosB  cosAsinB
then sin(uv) = sinucosv  cosusinv
= (5/13)(3/5)  (12/13)(4/5) = 63/65

Math  Hannah, Monday, March 29, 2010 at 11:03pm
Thank You
Answer This Question
Related Questions
 Math  Find the exact value of the trigonometric function given that sin u = 5/...
 Alg2/Trig  Find the exact value of the trigonometric function given that sin u...
 MATH  1.)Find the exact solution algebriacally, if possible: (PLEASE SHOW ALL ...
 PreCalc  I am really struggling with how to do these problems, I posted them a...
 PreCalc  1) Use an Addition or Subtraction Formula to write the expression as ...
 trig help much appreciated! :))  1. Find the complete exact solution of sin x...
 Mathematics  Trigonometric Identities  Let y represent theta Prove: 1 + 1/tan^...
 Trig  Find the exact value of the trigonometric function given that sin u=3/5 ...
 PreCalc  Hi, can someone please teach me how to solve this? Find the exact ...
 math  Eliminate the parameter (What does that mean?) and write a rectangular ...
More Related Questions