Given f(x,y)=|x-y^2+3| I'm asked to calculate df/dx and df/dy. f(x,y)=x-y^2+3 if x-y^2+3>=0 f(x,y)=-x+y^2-3 if x-y^2+3<0 df/dx=1 if x-y^2+3>=0 df/dx=-1 if x-y^2+3<0 df/dy=-2y if x-y^2+3>=0 df/dy=2y if x-y^2+3<0 Is it ok to say this?