1. Using a logical or graphical argument, prove Eq XXXXXXXXXXWhy can’t apparent frequency be computed as fa = 0>F s ? 2. A signal x(t) = 3 cos(6πt) + cos(16πt) + 2 cos(20πt) is sampled at a rate 25%...

1. Using a logical or graphical argument, prove Eq. (3.14). Why can’t apparent frequency be computed as fa = 0>F_s
?

2. A signal x(t) = 3 cos(6πt) + cos(16πt) + 2 cos(20πt) is sampled at a rate 25% above the Nyquist rate. Sketch the spectrum of the sampled signal. How would you reconstruct x(t) from these samples? If the sampling frequency is 25% below the Nyquist rate, what are the frequencies of the sinusoids present in the output of the filter with cutoff frequency equal to the folding frequency? Do not write the actual output; give just the frequencies of the sinusoids present in the output.