Express in terms of the unit step function, the piecewise continuous causal functions () = { 2 2 , 0 ≤ < 3 + 4, 3 ≤ < 5 9, ≥ 5 [3 marks] ii. Use Laplace transforms to solve the initial value problem ) ′′ + 16 = 43 + ( − ⁄3) where (0) = 0 and ′(0) = 0.