Consider the function defined by $\displaystyle f(x+iy) = \sqrt(\left |x \right |\left |y \right |)$. Show that $\displaystyle f$ satisfies the Cauchy-Riemann equations at the origin yet it is not holomorphic at zero.

I can show that it satisfies the C-R equations but unsure about showing it is not holomorphic at zero. Please help?