A continuous-time signal a(t) is shown in the figure below. Sketch and label carefully each of the following signals: (a) [x(t) + x(-1)]u(t) 2 -1 2 x(t) (b) r(t)u(t) + u(-1)] 2 3 3 -0.5 0.5 (c) r(t) [8(t+1)-8(t-1)] 1 2 0,5 3 0 4