다음 무한급수의 합은?

$\displaystyle 1- \frac{\pi ^ {2}} {2 ^ {2} ⋅ 3!} + \frac{\pi ^ {4}} {2 ^ {4} ⋅ 5!} - \frac{\pi ^ {6}} {2 ^ {6} ⋅ 7!} + \cdots$

• ①$\pi$
• ②$\displaystyle \frac{\pi} {2}$
• ③$\displaystyle \frac{2} {\pi}$
• ④$\displaystyle \frac{1} {\pi}$