Problem 1 (C-to-D Conversion) - 20 points:: Let x(t)=3cos(7t/4). In each of the following parts, the discrete-time signal x[n] is obtained by sampling x(t) at a rate fs samples/s, and the resultant x[n] can be written as x[n]=Acos(1n+) For each part below, determine the values of A,, and 1 such that 01. In addition, state whether or not the signal has been oversampled or under-sampled (a) Sampling frequency is fs=10 samples/s. Plot (b) Sampling frequency is fs=5 samples /s. (c) Sampling frequency is fs=2 samples /s