2002-22.md

course	course_year	question_number	tags	title	year
Complex Methods	IB	22	IB 2002 Complex Methods	2.I.7B	2002

Suppose that $f$ is analytic, and that $|f(z)|^{2}$ is constant in an open disk $D$. Use the Cauchy-Riemann equations to show that $f(z)$ is constant in $D$.