Problem 7.4* For each of the following systems, determine if they are (1) linear; (2) time-invariant; (3) causal. (a) $y[n] = 3x[n-1] + x[n] + 3x[n+1]$ (b) $y[n] = x[n] \cos(.3\pi n)$ (c) $y[n] = |x[-n]|$ (d) $y[n] = x[n-2] + 2x[n] + x[n+2]$ (e) $y[n] = nx[n]$ (f) $y[n] = (x[-n])^2$
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If we have two inputs x1[n] and x2[n], the output y[n] will be the sum of the outputs corresponding to each input. To check if it is time-invariant, we need to see if a time shift in the input results in a corresponding time shift in the output. In this case, if Show more…
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