数学求导数.

1,y=x²lnx-x
y'=2xlnx+x²*(1/x)-1
=2xlnx+x-1
2,y=lnx/x²
y'=(1/x*x²-lnx*2x)/(x²)²
=(x-2xlnx)/x^4
=(1-2lnx)/x³
3,y=sin(3x²+1)
y'=cos(3x²+1)×3×2x
=6xcos(3x²+1)