Suppose we are given the following information about a signal x(t):
1. x(t) is real and even
2. x(t) is periodic with period T = 4 and Fourier coefficients $ \ a_k $
3. $ \ a_k = 0 $ for $ \left | \frac{a}{b} \right \vert \left \Vert \frac{c}{d} \right \| $
4. $ stuff2 $
