# How do you determine where the function is increasing or decreasing, and determine where relative maxima and minima occur for # y=cos^2 x - sin^2 x#?

##### 1 Answer

Aug 20, 2016

see below

#### Explanation:

Well, first you simplify this

then it's just a periodic cosine, save that it has twice the frequency as it is the cosine of

graph{cos (2x) [-2.738, 2.736, -1.367, 1.37]}