SOLUTION: Please any answer is appreciated for the following: Prove that cos[3*pi/2 + x] = sinx THank You

Algebra ->  Trigonometry-basics -> SOLUTION: Please any answer is appreciated for the following: Prove that cos[3*pi/2 + x] = sinx THank You      Log On


   

Question 430780: Please any answer is appreciated for the following:
Prove that cos[3*pi/2 + x] = sinx
THank You
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Using the addition formula for cosine:

cos%283pi%2F2+%2B+x%29+=+cos%283pi%2F2%29cos%28x%29+-+sin%283pi%2F2%29sin%28x%29 Since cos%283pi%2F2%29+=+0 and sin%283pi%2F2%29+=+-1,

cos%283pi%2F2+%2B+x%29+=+0%2Acos%28x%29+-+%28-1%29%28sin%28x%29%29

= sin%28x%29.