Question

Show that sin (x + pi) = -sin x.

Answer 1

Answer:

The answer in the procedure

Step-by-step explanation:

we know that

$sin(A + B) = sin A cos B + cos A sin B$

In this problem we have

$sin(x + \pi)=sin (x)cos(\pi) + cos(x)sin(\pi)$

Remember that

$sin(\pi) = 0$

$cos(\pi) = -1$

substitute

$sin(x + \pi) = sin(x)(-1) + cos(x)(0)$

$sin(x + \pi) = -sin(x)$