Chapter 5.6, Problem 8P

In each of Problems $1$ through $13$, find the solutions of the given initial value problem. Draw the graphs of the solution and of the forcing function; explain how they are related.

$y\text{'}\text{'}+y\text{'}+1.25y=t-u_{\pi /2}(t)(t-\pi /2);$

$y(0)=0,$ $y\text{'}(0)=0$