2019-7.md

course	course_year	question_number	tags	title	year
Complex Analysis	IB	7	IB 2019 Complex Analysis	Paper 4, Section I, $4 \mathbf{F}$	2019

State the Cauchy Integral Formula for a disc. If $f: D\left(z_{0} ; r\right) \rightarrow \mathbb{C}$ is a holomorphic function such that $|f(z)| \leqslant\left|f\left(z_{0}\right)\right|$ for all $z \in D\left(z_{0} ; r\right)$, show using the Cauchy Integral Formula that $f$ is constant.