求导数得到dz/dx=dz/du *du/dx +dz/dv *dv/dx=v *e^uv *(x^3)' +u *e^uv *(sinx)'而(x^3)'=3x^2，(sinx)'=cosx所以dz/dz=v *e^uv *3x^2 +u *e^uv *cosx
