JEE Main 20262 AprilMorning Shift
- Exam
- JEE Main
- Year
- 2026
- Date
- 2 April
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Quadratic Equation
JEE Main 2026 · 2 April · Morning Shift · Mathematics · Quadratic Equation
Let a, b, c ∈ \ 1, 2, 3, 4\ . If the probability, that ax^2 + 2 2...
Let . If the probability, that for all , is , , then is equal to _______.
Correct answer
0
Step-by-step solution
For the quadratic expression for all , the leading coefficient must be positive and the discriminant must be negative.
Since , the condition is always satisfied.
The discriminant condition is:
The total number of possible triplets is .
Now, we find the number of favorable outcomes by checking the possible values of :
Case 1:
We need .
The total number of pairs is .
The pairs for which are , which are in number.
So, the number of pairs with is .
Case 2:
We need .
The possible pairs from the given set are .
So, there are pairs.
Case 3:
We need .
Since the maximum possible value of is , there are pairs.
Case 4:
We need .
Again, there are pairs.
Total number of favorable outcomes = .
The required probability is .
Since , we have and .
Therefore, .
Answer:
Since , the condition is always satisfied.
The discriminant condition is:
The total number of possible triplets is .
Now, we find the number of favorable outcomes by checking the possible values of :
Case 1:
We need .
The total number of pairs is .
The pairs for which are , which are in number.
So, the number of pairs with is .
Case 2:
We need .
The possible pairs from the given set are .
So, there are pairs.
Case 3:
We need .
Since the maximum possible value of is , there are pairs.
Case 4:
We need .
Again, there are pairs.
Total number of favorable outcomes = .
The required probability is .
Since , we have and .
Therefore, .
Answer: