演習問題5.3.2

1.
次の初期値問題の解のラプラス変換を求めよ.
(a)
$\displaystyle{ y^{\prime\prime} + 4y^{\prime} - 5y = e^{t},  y(0) = 0,  y^{\prime}(0) = 1}$
(b)
$\displaystyle{ y^{\prime\prime} + 4y^{\prime} + 4y = e^{-t},  y(0) = 1,  y^{\prime}(0) = 1}$
(c)
$\displaystyle{ y^{\prime\prime} + 4y^{\prime} - 5y = f(t),  y(0) = 0,  y^{\prime}(0) = 0}$

$\displaystyle f(t) = \left\{\begin{array}{rl}
2,&0 < t < \pi\\
\cos{t},&t > \pi
\end{array} \right. $