JEE MAIN - Mathematics (2025 - 29th January Evening Shift - No. 20)
Let the function $f(x)=\left(x^2-1\right)\left|x^2-a x+2\right|+\cos |x|$ be not differentiable at the two points $x=\alpha=2$ and $x=\beta$. Then the distance of the point $(\alpha, \beta)$ from the line $12 x+5 y+10=0$ is equal to :
5
2
4
3
Explanation
$\cos |\mathrm{x}|$ is always differentiable
$\therefore$ we have to check only for $\left|\mathrm{x}^2-\mathrm{ax}+2\right|$
$\therefore$ Not differentiable at
$$x^2-a x+2=0$$
One root is given, $\alpha=2$
$$\begin{aligned} \therefore \quad 4 & -2 a+2=0 \\ & a=3 \end{aligned}$$
$\therefore$ other root $\beta=1$
but for $x=1 f(x)$ is differentiable
(Drop)
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