Consider a periodic half-rectified sine wave, defined by [Asin(27) 051s SISI for all integer values, k With x(t)=x(t+k) a) Find the coefficients of the complex exponential Fourier series of x(t). [9] b) If x() is fed into an ideal lowpass filter with a bandwidth of 3.5Hz, with gain of 1 in the passband, compare the power of the signal at the output of the lowpass filter with that of x(1). [6] c) Sketch the double sided, power spectrum density of the signal at the output of the lowpass filter.