For each x(t) shown in Figure 1 (see the last page), express x(t) as a linear combination of (shifted) steps and ramps. Sketch the following continuous-time signals. (a) x(t) = u (t + 4) - 3 u (t + 1) + 3 u (t) - u (t - 1) - 2u (t - 3) + u (t - 5) (b) x(t) = 2r(t) - r(t - 1) - r (t - 2) - 2r (t - 3) + r (t - 5) + 3 r (t - 6) - 2r (t - 7) (c) x(t) = u (t - 1) + r (t - 1) - r (t - 2) + u (t - 3) - r (t - 3) - u (t - 4) + r (t - 5) (d) x(t) = tu (t - 1) - (t - 2) u (t - 2) - (t - 4) u (t - 3) - u(t - 4) + (t - 5) u (t - 5) Use MATLAB to plot the signals in problem 2. Use Matlab to plot the following functions for -1 lessthanorequalto t lessthanorequalto 7 sec. Label your axes appropriately. (a) x(t) = {-t^2 + 4t 0 lessthanorequalto t