Question

Which of the following is a step in evaluating
ç(integer sign) cos^2 5x dx
A.ç(integer sign) 1 + cos 10x / 2 dx
B.ç(integer sign) 1 - cos 10x / 2 dx
C.ç(integer sign) 1 + cos 10x / 20 dx
D.ç(integer sign) 1 - cos 10x / 20 dx


A <<

Answer 1

Correct.

A.
∫(1 + cos(10x))/2 dx

using
cos(a)cos(b)=(1/2)(cos(a-b)+cos(a+b))

Answer 2

Thank you.