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Find the Least Positive Value Of K For Which the Equation X2 + Kx + 4 = 0 Has Real Roots. - CBSE Class 10 - Mathematics

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Question

Find the least positive value of k for which the equation x2 + kx + 4 = 0 has real roots.

Solution

The given quadric equation is x2 + kx + 4 = 0, and roots are real.

Then find the value of k.

Here,

a = 1, b = k and c = 4

As we know that D = b2 - 4ac

Putting the value of a = 1, b = k and c = 4

= k2 - 4 x (1) x (4)

= k2 - 16

The given equation will have real and equal roots, if D = 0

k2 - 16 = 0

Now factorizing of the above equation

k2 - 16 = 0

k2 = 16

`k=sqrt16`

k = ± 4

Now according to question, the value of k is positive.

Therefore, the value of k = 4

  Is there an error in this question or solution?

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Solution Find the Least Positive Value Of K For Which the Equation X2 + Kx + 4 = 0 Has Real Roots. Concept: Nature of Roots.
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