$X=X (t)$ 가 연립미분방정식 $\displaystyle X ' (t) = \begin{pmatrix*}[r] 1 & 2 \\ - \frac{1} {2} & 1 \end{pmatrix*} X (t), X (0) = \left (\begin{matrix*}[r] 1 \\ 1 \end{matrix*} \right)$

의 해일 때, $X (\pi / 2)$ 를 구하면?

• ①$\displaystyle \left (\begin{matrix*}[r] 2 e^ {\frac{\pi} {2}} \\ - \frac{1} {2} e^ {\frac{\pi} {2}} \end{matrix*} \right)$
• ②$\displaystyle \left (\begin{matrix*}[r] 2 e^ {\frac{\pi} {2}} \\ \frac{1} {2} e^ {\frac{\pi} {2}} \end{matrix*} \right)$
• ③$\displaystyle \left (\begin{matrix*}[r] - \frac{1} {2} e ^ {\frac{\pi} {2}} \\ 2e ^ {\frac{\pi} {2}} \end{matrix*} \right)$
• ④$\displaystyle \left (\begin{matrix*}[r] \frac{1} {2} e^ {\frac{\pi} {2}} \\ 2 e^ {\frac{\pi} {2}} \end{matrix*} \right)$