Fourier series:
Input CT signal: x(t) = 3cost+sin2t
=$ 3*\frac{e^jt+e^-jt}{2}+\frac{e^j2t-e^-j2t}{2}\, $ =$ \frac{3}{2}e^{jt}-\frac{3}[2}e^{-jt}+\frac{1}{2}e^{j2t}-\frac{1}{2}e^{-j2t} $
