JEE MATHEMATICS MCQ: QUADRATIC EQUATIONS

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Application +4 | -1

{x^2} + 4ax + 2 > 0

for all values of

x

, then

a

lies in the interval

View answer and explanation

Correct option: D

\left( { - \frac{1}{{\sqrt 2 }},\;\frac{1}{{\sqrt 2 }}} \right)

Option D (

\left( { - \frac{1}{{\sqrt 2 }},\;\frac{1}{{\sqrt 2 }}} \right)

) is correct because for the quadratic to be always positive, the discriminant must be negative, leading to the given interval for

a

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