cos (x + pi) is equal to

Question

cos (x + pi) is equal to

Answer 1

Greetings! Lets solve this shall we ?

So, we must use a trig identity to simplify this equation. Hence, we use

cos(u+v) = cos(u)cos(v) - sin(u)sin(v) such that,

cos(x+π) = cos(x)cos(π) - sin(x)sin(π)

cos(x+π) = cos(x)(-1) - sinx(0)

cos(x+π) = - cos(x)

I hope this helped!