Satisfies Cauchy-Riemann equations but not differentiable

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SUMMARY

The function f(z) defined as f(z) = z^2/z for z ≠ 0 and f(0) = 0 satisfies the Cauchy-Riemann equations at z = 0 but is not differentiable there. The proof involves demonstrating that the limit f'(0) = lim_{h -> 0} ((f(h) - f(0))/h) does not exist. By approaching zero along different paths, it is shown that the limit yields different results, confirming the lack of differentiability at that point.

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Homework Statement


Let f denote the function defined by
f(z)=
_z^2 /z if z is not 0
0 if z=0
show that f satisfies the Cauchy-Riemann equations at z=0 but that f is not differentiable there

Homework Equations





The Attempt at a Solution


it is easily to show the function satisfies Cauchy-Riemann equations
but how to show it is not differentiable
can i show f'(0) does not exist when z tends to 0 ?
 
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_z is x-iy
 
What you need to show is that f'(0) = lim_{h -> 0} ((f(h) - f(0))/h = lim_{h -> 0} _h^2/h^2. does not exist. To show that this limit does not exist, try approaching 0 in two different ways and show you get something different.
 

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