The systems that follow have input x(t) or x[n] and output y(t) or y[n]. For each system, determine step by step whether it is (i) memoryless, (ii) stable, (iii) causal, (iv) linear, and (v) time invariant.
a) y(t) = cos(x(t))
b) y[n] = log10(|x[n]|)
c) y(t) = x(2 - t)