Let $z$ be a complex number. Is
\begin{equation} |\exp(z)| \geq \exp(-|z|) \end{equation}
for arbitrary $z$ or do we need a condition on $z$?
How can one prove this? I tried the inverse triangle inequality but couldn't do it.
Let $z$ be a complex number. Is
\begin{equation} |\exp(z)| \geq \exp(-|z|) \end{equation}
for arbitrary $z$ or do we need a condition on $z$?
How can one prove this? I tried the inverse triangle inequality but couldn't do it.
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Hint: $|\exp(z)| = \exp (\Re (z)).$ $~~~$Thus,
$\exp (\Re (z)) \geq \exp \left(-\sqrt{\Re ^2(z)+\Im^2 (z)}\right) \implies \Re (z) \geq -\sqrt{\Re ^2(z)+\Im^2 (z)}.$
$\Re (z)$ and $\Im (z)$ are the real and imaginary parts of $z$.