The value of $\alpha$ for which the sum of the squares of the roots of the equation $x^2-(a-2) x-a-1=0$…
The value of $\alpha$ for which the sum of the squares of the roots of the equation $x^2-(a-2) x-a-1=0$ assume the least value is
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1
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0
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3
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2
Solution
$
\begin{aligned}
& x^2-(a-2) x-a-1=0 \\
& \Rightarrow \alpha+\beta=a-2 \\
& \alpha \beta=-(a+1) \\
& \alpha^2+\beta^2=(\alpha+\beta)^2-2 \alpha \beta \\
& \quad=a^2-2 a+6=(a-1)^2+5 \\
& \Rightarrow a=1 .
\end{aligned}
$
Asked in: JEE Main 2005
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