Question 3 [10 points] For the given signals, determine if it is periodic, find the fundamental period $T_0$ and the fundamental frequency $W_0$. Otherwise, show that the signal is not periodic.\
a) $x(t) = cos(t) + sin(\pi t)$\
b) $x(t) = x_1(t) + x_2(3t)$ where $x_1(t) = sin(\frac{\pi t}{6})$ and $x_2(t) = sin(\frac{\pi t}{9})$.