z=f(xy,y)的偏導數d^z/dxdy

z=f(xy,y)的偏導數d^z/dxdy

由題知,
z=f(xy,y)
所以,
dz/dx=f1(xy,y)*y

d²;z/dxdy
=d(dz/dx)/dy
=d(f1(xy,y)*y)/dy
=f1(xy,y)+y[f11(xy,y)*x+f12(xy,y)]
=f1+xy*f11+y*f12
其中,f(u,v)對u求導記做f1,對y求導記做f2