解:一定要注意外层求导后,要内层求导y=f(x^2),dy/dx=2xf'(x^2)所以d^2y/dx^2=2f'(x^2)+2xf''(x^2)2x=2f'(x^2)+4x^2f''(x^2)还有问题继续讨论望您能采纳
dy/dx = 2xf'(x^2)d^2y/dx^2 = d(2xf'(x^2))/dx = 2f'(x^2) + 4x^2f''(x^2)这些都是套用复合函数导数公式而已,lz应该能自己搞出来