Please show work

4). Solve y\" + 23f + 23; = 9(t) with 19(0) = 0, y'(0] = 0, and g(t) a function; express the solution with the help of convolution. 5). i. Find the steady state solution for y\" + 23," + 173; = cos wt. ii. Find the amplitude of the steady state solution. iii. Find w > 0 so that the amplitude of the steady state solution is maximal