Given an analog signal x(t) = 5 cos(5000pit) + 2 cos(6400pit) , for t>=0 sampled at a rate of 8000 Hz. a. Sketch the spectrum of the original signal and the sampled signal from 0 kHz and 25 kHz. b. Sketch the recovered analog signal spectrum if an ideal lowpass filter with a cutoff frequency of 4 kHz is used to filter the sampled signal. X(f) 10k 20k 25k f(Hz)