Find one complex number w such that w is not in the range of f(z)= e^z, and explain why this number is not in the range of f(z).

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- Sep 29th 2010, 06:08 PMrdoss30Complex Analysis: find one complex number w such that w is not in the range f(z)= e^z
Find one complex number w such that w is not in the range of f(z)= e^z, and explain why this number is not in the range of f(z).

- Oct 2nd 2010, 01:54 PMHappyJoe
Take w=0.

The exponential function is never 0. Why? Write x = x+iy. Then e^z = e^x(cos(y)+isin(y)). Here e^x is the usual real exponential, which is well-known never to be 0. And cosine and sine are also well-known never to be 0 simultaneously, hence e^z is non-zero for all z.