$\displaystyle \int _ {0} ^ {1} {\int _ {\sqrt y} ^ {1} {e^ {x^3}}} dxdy$ 의 값은?

• ①$\displaystyle \frac{1} {2} \left (e-1 \right)$
• ②$\displaystyle \frac{1} {2} \left (e+1 \right)$
• ③$\displaystyle \frac{1} {3} \left (e-1 \right)$
• ④$\displaystyle \frac{1} {3} \left (e+1 \right)$