选择题
2.设y=y(x)由x-∫1x+ye-t2dt=0确定，则y''(0)等于( )．
【正确答案】
A
【答案解析】当x=0时，由-∫1ye-t2dt=0得y=1，
x-∫1x+ye-t2dt=0两边对x求导得1-e-(x+y)2.
=0，
解得
=e(x+y)2-1，且
=e-1．
由
=e(x+y)2.2(x+y).
得y''(0)=
x-∫1x+ye-t2dt=0两边对x求导得1-e-(x+y)2.
=0，解得
=e(x+y)2-1，且=e-1．由
=e(x+y)2.2(x+y).得y''(0)=