Answer Happy

(a) (4 marks) Determine whether or not the following signals are periodic. If a signal is periodic, specify its fundamental period. = (i) (2 marks) xi(t) = ſejat + e-jnt] cos(at). (ii) (2 marks) 22 [n] = sin((62n) + 1], n e Z. (b) (12 marks) Below show six system equations, where the input and output are given by æ(t) and y(t), respectively. For each of the equations, determine if the corresponding system is time-invariant or time-varying, and explain your reasons. (i) (2 marks) y(t) = tæ(t) (ii) (2 marks) y(t) = x(t – 2) (iii) (2 marks) y(t) = $5 *(T)dt (iv) (2 marks) y(t) = x(-t) (v) (2 marks) y(t) = dinle, 2 dt2 (vi) (2 marks) y(t) = x(at) (c) (4 marks) Find the power of the periodic signal f(t) shown in Figure 1 and the power of cf(t), where c is a constant. f(t) Hirt r 2 Figure 1: The plot of f(t) for Problem 1(c).