$\displaystyle \int _ {-2} ^ {0} {\int _ {-x} ^ {2} {e^ {y^2} dy dx}}$ 의 값은?

• ①$\displaystyle \frac{1} {2} (e^4 -1)$
• ②$\displaystyle \frac{1} {3} (e^4 -1)$
• ③$\displaystyle \frac{1} {4} (e^4 -1)$
• ④$e^4 -2$
• ⑤$e^4 -1$