Question

Prove that sin(x + pi) = -sinx *show work

Answer 1

Answer:

Step-by-step explanation:

Use the identity $sin(a+b)=sin a cosb+sinbcosa$ where $a=x$ and $b=\pi$.

This results in $sinxcos\pi +sin\pi cosx$

From the unit circle we know that $cos\pi =-1$ and $sin\pi =0$

Substitute

$sinx(-1)+(0)cosx$

Simplify

$-sinx$