When evaluating the integral Sin^m xCos^n xdx, which formula or law is most useful if the powers of both sin and cosine are even?

Question

anonymous · Answer

If I remember correctly:
$$sin^2x+cos^2x=1$$
You can solve for either and substitute, but it's been a few since I did those problems and I hated trig based integrals ;)

anonymous · Answer

Hmm, looked it up. My bad. It's the half angle identities.

anonymous · Answer

$$sin^2x=\frac{1-cos(2x)}{2}$$
and
$$cos^2x=\frac{1+cos(2x)}{2}$$

anonymous · Answer

The first answer I listed is for use in odd problems.

amistre64 · Answer

i think they also call it reducing powers?

anonymous · Answer

Half Angle Formula got it!