Previous examples explained how to integrate terms involving a trigonometric function raised to odd-numbered powers. But what do we do when multiple functions are all raised to an even-numbered power?
These problems will be solved by using the 'Power Reducing' or 'Half Angle' identity function to reduce the power of the trigonometric function. From that point, it is a matter of using substitutiion to solve the remainder of the problem.
For example, we solve:
$\int {sin}^{2}x\phantom{\rule{3px}{0ex}}{cos}^{2}x\phantom{\rule{3px}{0ex}}dx$
Multiple Trig Functions Raised to Even-Numbered Powers