1. Question: Sketch the continuous-time signals: - (a) x(t) = u(t + 1) - 2u(t − 1) + u(t − 3) (b) x(t) = (t+1)u(t − 1) - tu(t) - u(t - 2) (c) x(t)=2(t 1)u(t - 1) - 2(t − 2)u(t − 2) + 2(t − 3)u(t - 3) 2. Question: For each of the following systems, determine whether the system is (1) linear (2) time invariant (3)memoryless, (4)stable, and (5) casual. (a) y(t) = ex(t) (b) = y(t) = ={ x(t) |x(t)| ≤ 10 10 x(t) > 10 (c) y(t) = f(ta)x(a)da 3. Question: For each of the following systems, determine whether the system is (1) linear (2) time invariant (3)memoryless, (4)stable, and (5) casual. (a) y(t) = |x(t)| (b) y(t) = sin tx(t) rt+1 (c) y(t) = f**¹ x(a)da (d) y(t) = x(t) dt