For each of the following signals, determine which is periodic and which is NOT. For those that are periodic, find the fundamental frequency.
a) x(t) = cos(5ωt) + sin(15ωt)
b) x(t) = 5t - 2cos(5ωt)
c) x(t) = 2 + 10sin(5t) - 4cos(7t)
For those signals that are periodic, find the complex exponential Fourier coefficients (i.e. find Dn) and also find the total average power.