Text: Question 3.
a) Consider the following ODE:
y''(t) + 2y'(t) = r(t), if t < 5
y(t) = 5, if t ≥ 5
with r(t) = 3 - u(t - 5) and initial condition y(0) = 10. Recall that u(t - 5) is the unit step function.
(i) (5 marks) Find Y(s) = L{y(t)}, the Laplace transform of y(t).
(ii) (8 marks) Find y(t) by computing the inverse Laplace transform of Y(s).
(iii) (2 marks) Find lim(t→∞) y(t).
b) (4 marks) Find the Laplace transform of f(t) = t cos(3t). Justify your answer.