Find the Laplace transform Y(s)=L{y} of the solution of the given initial value problem.
y′′ + 4y = { t, 0 ≤ t < 1
{ 1, 1 ≤ t < ∞, y(0) = 3, y′(0) = 3
Enclose numerators and denominators in parentheses. For example, (a−b)/(1+n).
Y(s)= _______________