Function
$ \,y = cos(x) $
Signal Energy
$ \,Energy = \int_0^{2\pi}{|cos(x)|^2dx} $
- $ \, = \int_0^{2\pi}{|\frac{1+cos(2x)}{2}|dx} $
- $ \, = \frac{1}{2}\int_0^{2\pi}{(1 + cos(2x))dx} $
- $ \, = \frac{1}{2}(x + \frac{1}{2}sin(2x))|_0^{2/pi} $
- $ \, = \frac{1}{2}(2\pi + 0 - 0 - 0) $
- $ \, = \pi $
