Can you guys help. I haven't done this stuff in a while.
How would you integrate:
(sin x)^2
Thanks if you can shed light.
$\displaystyle \cos(2x)=\cos^2(x)-\sin^2(x)$
from that we can replace
$\displaystyle \cos^2(x)=1-\sin^2(x)$
to get
$\displaystyle \cos(2x)=1-2\sin^2(x)$
From there you can find what they said
so
$\displaystyle \int\sin^2(x)dx=\int\frac{1-\cos(2x)}{2}dx=\frac{x}{2}-\frac{1}{2}\int\cos(2x)dx$
for the last one isolate the derivative of the quanity and be done with it =D