Sketch the following: a) y = u(t-1)-u(t - 4) b) y = [u(t-1)-u(t - 4)](-t+3) c) f(t) = {- +²+3, -2, -1≤t<1 1 ≤ t < 4 d) t² + 1, 0 ≤ t < 1 Given h(t) = ln t, t21 0, Otherwise (1) Sketch the graph h (t) on appropriate set of axes Find the value of t for which h(t) = 6 (ii)