Are the Cauchy-Riemann Equations Ever Satisfied for f(z) = |z|?

[icystrike]

Homework Statement

What does it mean by this:
The cauchy riemann equations are never satisfied when x and y are different from zero and when x=y=0 .

Looking at the example of f(z)= l z l = $$\sqrt{x^{2}+y^{2}}$$

Homework Equations

The Attempt at a Solution

 

[hunt_mat]

write f(z)=u(x,y)+iv(x,y) and compute the derivatives, when are the CR equations satisfied?