# Math Help - addition or subtraction for cofunction identity

1. ## addition or subtraction for cofunction identity

I have no idea how to work this problem using addition or subtraction theories

(x-n) = -sin x

Thanks!

2. Originally Posted by pmacp
I have no idea how to work this problem using addition or subtraction theories

(x-n) = -sin x

Thanks!
What are you trying to do? What is the whole the question verbatim?

3. Prove the confunction identity sin (x - π) = -sin x using the addition or subtraction formulas.

4. $sin(x-\pi)=sin(x)cos(\pi)-cos(x)sin(\pi)=-sin(x)$

5. thank you!