Example 1
| 0, 0<=t<5
Example 1: solve 2y" + y' + 2y = | 1, 5<=t<20
| 0, 20<=t
u(0) = 0; u'(0) = 0
Example 2
| 0, 0<=t<5
Example 2: solve y" + 4y = | (t-5)/5, 5<=t<10
| 1, 10<=t
u(0) = 0; u'(0) = 0
