Sketch the following waveforms:

(a) vi(t) =r(t + 2) - r(t - 2) V P-40
(b) vz(t) = 4 + r(t + 1) - 2r(t - 1) + r(t - 3) V dvi(t)
(c) 03(t) = d v1(t) /dt
(d) v4(t) = d²v2(t) / dt²