I am reading signal processing first and in chapter 3 ex3.8 i came across an example of fundamental period as shown in attached photo
It apparently shows that signal $$x(t)=\cos^2(4\pi t)$$ has period 0.5 but then it also writes that fundamental period is 0.25
How is he doing that?
Also will be fundamental period if $$x(t)=\cos^n(4\pi t)$$ where n can be 3 or 4 or 5