Q. A circle $C_1$ passes through the origin $O$ and has diameter 4 on the positive $x$-axis. The line $y =2 x$ gives a chord $OA$ of a circle $C _1$. Let $C _2$ be the circle with $OA$ as a diameter. If the tangent to $C _2$ at the point $A$ meets the $x$-axis at $P$ and $y$-axis at $Q$, then QA : AP is equal to :
Solution:
