∫∫e^（-y^2/2)dv=∫[0,1]e^（-y^2/2)dy∫[y^2,1]dx=∫[0,1](1-y^2)*e^（-y^2/2)dy
=∫[0,1]e^（-y^2/2)dy-∫[0,1]y^2*e^（-y^2/2)dy
前一项进行分部积分
=y*e^（-y^2/2) |[0,1]+∫[0,1]y^2*e^（-y^2/2)dy-∫[0,1]y^2*e^（-y^2/2)dy
=e^(-1/2)
[ , ]表示[下限,上限]
可能运算时出错,方法应该是对的,仅供参考.