Periodic CT Signal and Its Fourier Coefficients
Take the signal $ x(t) = 5cos(2t) - 4sin(2t) $. The graph below proves that it is indeed periodic, with a period $ T = \pi $.
$ \,\ sin(x) = \frac{1}{2j} * (e $(jx) $ \,\ - e $(-jx)$ \,\ ) $
and
$ \,\ cos(x) = \frac{1}{2} * (e $(jx) $ \,\ + e $(-jx)$ \,\ ) $
Therefore,
$ x(t) = 5 * \frac{1}{2} * (e $(j2t) $ \,\ + e $(-j2t)$ \,\ ) - 4 * \frac{1}{2j} * (e $(j2t) $ \,\ - e $(-j2t)$ \,\ ) $
The period $ \,\ T = \pi $ so if $ \,\ w_0 = \frac{2\pi}{T} $, then $ \,\ w_0 = 2 $.
