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Complex Numbers and Quadratic Equations — Maths STD 11 Science — Question

CBSE BoardEnglish MediumSTD 11 ScienceMathsComplex Numbers and Quadratic Equations1 Mark
MCQ
Roots of a quadratic equation are real when discriminant is $............$
  • A
    zero
  • B
    greater than zero
  • C
    less than zero
  • ✓
    greater than or equal to zero
✓

Answer

Correct option: D.
greater than or equal to zero
For a quadratic equation, $a x^2+b x+c=0$, discriminant is $b^2-4 a c$.
Roots are $\frac{-\text{b}\pm\sqrt{\text{b}^2-4\text{ac}}}{2\text{a}}$ For real roots,
radical must be non$-$negative
i.e. discriminant should be greater than or equal to zero.

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