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Find the discriminant of the quadratic e...

Find the discriminant of the quadratic equation `2x^2-4x+3=0`, and hence find the nature of its roots.

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Verified by Experts

The correct Answer is:
D

Let `f(x)=x^(2)-8kx+16(k^(2)-k+1)` brgt
`:.Dgt0`
`implies64k^(2)-4.16(k^(2)-k+1)gt0`
`implieskgt1` …….i
`implies(-b)/(2a)gt4implies(8k)/2gt4`
`implieskgt1`………….ii
and `f(4)ge0`
`implies16-32k+16(k^(2)-k+1)ge0`
`impliesk^(2)-3k+2ge0`
`implies(k-1)(k-2)ge0`
`kle1` or `kge2`...........iii
From Eqs i, ii and iii we get
`kge2`
`k_("min")=2`
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ARIHANT MATHS-THEORY OF EQUATIONS-Exercise (Questions Asked In Previous 13 Years Exam)
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  3. Find the discriminant of the quadratic equation 2x^2-4x+3=0, and hence...

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  6. solve 0=-1+2x+3x^2

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  7. Find the roots of x^2-6x-2=0

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  12. Let alpha(a) and beta(a) be the roots of the equation ((1+a)^(1/3)-1)x...

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  13. Find the roots of x^2+7x+12=0

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  14. If the equation x^2+2x+3=0 and ax^2+bx+c=0 have a common root then a:...

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  15. Solve x^2+3x+9=0

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  16. Let alpha and beta be the roots of equation px^(2) + qx + r = 0 , ...

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  17. Let a in R and f : R rarr R be given by f(x)=x^(5)-5x+a, then (a) f...

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