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NDA 2021
Exam
NDA
Year
2021
Subject
Mathematics
Chapter
Quadratic Equation

NDA 2021 · Mathematics · Quadratic Equation

If the roots of the quadratic equation x^2+2 x+k=0 are real, then

If the roots of the quadratic equation x2+2x+k=0x^2+2 x+k=0 are real, then

Options

  1. Ak<0k < 0
  2. Bk≤0k \leq 0
  3. Ck<1k < 1
  4. Dk≤1k \leq 1

Correct answer

D. k≤1k \leq 1

Step-by-step solution

Roots are real, if D≥0(−2)2−4k≥0⇒(1−k)≥0⇒k≤1D \geq 0(-2)^2-4 k \geq 0\Rightarrow(1-k) \geq 0 \Rightarrow k \leq 1
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