JEE Main · 2019 · 12 Jan 2019 · Shift 2 · Quadratic Equations and Inequalities

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The number of integral values of for which the quadratic expression, , is always positive, is :
  1. (A)3
  2. (B)8
  3. (C)7✓ Correct
  4. (D)6

Answer: (C)

Solution

For to stay positive for all real , the leading coefficient must be positive, , and the discriminant negative. The discriminant condition simplifies to , i.e. , roughly . Combined with , the integer values are seven of them.

JEE Main · 2019 · 12 Jan 2019 · Shift 2 · Single correct option

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