Verified Solution • 2025–26 Session moderate

QJEEM22Ma2bcc: JEE Main 2022 Mathematics - Class 12 JEEM22Ma2bcc Solution: If the numbers appeared on the two throws of a fair six faced…

If the numbers appeared on the two throws of a fair six faced die are α and β, then the probability that x2+αx+β>0, for all x∈R, is :

Multiple Choice Options

  • A 1736
  • B 49
  • C 12
  • D 1936

Step-by-Step Verified Solution

For x^{2}+\alpha x+\beta>0 \forall x \in R to hold, we should have \alpha^{2}-4 \beta<0

If α=1,β\alpha=1, \beta can be 1, 2, 3, 4, 5, 6 i.e., 6 choices

If α=2,β\alpha=2, \beta can be 2, 3, 4, 5, 6 i.e., 5 choices

If α=3,β\alpha=3, \beta can be 3,4,5,63,4,5,6 i.e., 4 choices

If α=4,β\alpha=4, \beta can be 5 or 6 i.e., 2 choices

If α=6\alpha=6 , No possible value for β\beta i.e., 0 choices

Hence total favourable outcomes

=6+5+4+2+0+0=17

Total possible choices for α\alpha and β=6×6=36\beta=6 \times 6=36

Required probability =1736=\frac{17}{36}

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