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 :
Solution
<p>$\cos |\mathrm{x}|$ is always differentiable</p>
<p>$\therefore$ we have to check only for $\left|\mathrm{x}^2-\mathrm{ax}+2\right|$</p>
<p>$\therefore$ Not differentiable at</p>
<p>$x^2-a x+2=0$</p>
<p>One root is given, $\alpha=2$</p>
<p>$$\begin{aligned}
\therefore \quad 4 & -2 a+2=0 \\
& a=3
\end{aligned}$$</p>
<p>$\therefore$ other root $\beta=1$</p>
<p>but for $x=1 f(x)$ is differentiable</p>
<p>(Drop)</p>
About this question
Subject: Mathematics · Chapter: Limits, Continuity and Differentiability · Topic: Limits and Standard Results
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