jee-main 2018 Q61

jee-main · India · 15apr Solving quadratics and applications Optimization or extremal value of an expression via completing the square

If $\lambda \in R$ is such that the sum of the cubes of the roots of the equation $x ^ { 2 } + ( 2 - \lambda ) x + ( 10 - \lambda ) = 0$ is minimum, then the magnitude of the difference of the roots of this equation is :
(1) $4 \sqrt { 2 }$
(2) 20
(3) $2 \sqrt { 5 }$
(4) $2 \sqrt { 7 }$

If $\lambda \in R$ is such that the sum of the cubes of the roots of the equation $x ^ { 2 } + ( 2 - \lambda ) x + ( 10 - \lambda ) = 0$ is minimum, then the magnitude of the difference of the roots of this equation is :\\
(1) $4 \sqrt { 2 }$\\
(2) 20\\
(3) $2 \sqrt { 5 }$\\
(4) $2 \sqrt { 7 }$

Paper Questions

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