Question bank/JEE Advanced/Mathematics

Consider the region $R=\left\{(x, y) \in \mathbb{R} \times \mathbb{R}: x \geq 0\right.$ and $\left.y^2 \leq 4-x\right\}$. Let $\mathcal{F}$ be the family of all circles that are contained in $R$ and have centers on the $x$-axis. Let $C$ be the circle that has largest radius among the circles in $\mathcal{F}$. Let $(\alpha, \beta)$ be a point where the circle $C$ meets the curve $y^2=4-x$. What is the value of $\alpha$?

Source: JEEBench (IIT Delhi) / JEE Adv 2021 Paper 2