Chapter 4.7, Problem 11P

In each of Problems 10 through 13, use the method of variation of parameters to find a particular solution of the given differential equation. Then check your answer by using the method of undetermined coefficients.

$y\text{'}\text{'}-y\text{'}-2y=2e^{-t}$     (Compare with Problem 8 in Section 4.5.)

8. $y\text{'}\text{'}-y\text{'}-2y=2e^{-t}$     (Compare with Problem 11 in Section 4.7.)