Question

evaluate the integral from 0 to 2pi, cos^(2)(6theta) dtheta

Answer 1

You need to use the half angle formula which says:
\[\cos^2(x)=\frac{1}{2}(1+\cos(2x))\]
Applying this we have:
\[\frac{1}{2}\int\limits_0^{2\pi}1+\cos(12 \theta)d \theta=\frac{1}{2}[\theta+\frac{1}{12}\sin(12\theta)]_0^{2\pi}\]
You do the arithmetic :P

Answer 2

omgsh thank u!

Answer 3

No problem :P