Let $C_1$ be a fixed circumference with equation $(x-1)^2 + y^2 = 1$ and $C_2$ a circumference to be shrinked, with center at $(0, 0)$ and radius $r$.
Let $P$ be the point $(0, r)$, $Q$ the upper intersection between $C_1$ and $C_2$ and $R$ the intersection between the line $PQ$ with the $x$ axis.
What happens with $R$ when $C_2$ shrinks (i.e., $r \rightarrow 0^+$) ?