2007-16.md

course	course_year	question_number	tags	title	year
Geometry	IB	16	IB 2007 Geometry	3.I $2 \mathrm{~A} \quad$	2007

Let $l$ be a line in the Euclidean plane $\mathbf{R}^{2}$ and $P$ a point on $l$. Denote by $\rho$ the reflection in $l$ and by $\tau$ the rotation through an angle $\alpha$ about $P$. Describe, in terms of $l, P$, and $\alpha$, a line fixed by the composition $\tau \rho$ and show that $\tau \rho$ is a reflection.