If is a twice differentiable function such that for all , and , then
- (A)
- (B)
- (C)
- (D)✓ Correct
Answer: (D)
Solution
Since for all , the function is strictly convex.
Consider . We have:
By Rolle's theorem, there exists such that , i.e., .
Since , we have is strictly increasing.
Therefore, for :
In particular, .
Consider . We have:
By Rolle's theorem, there exists such that , i.e., .
Since , we have is strictly increasing.
Therefore, for :
In particular, .
JEE Advanced · 2017 · 21 May 2017 · Paper 2 · Single correct option