Let be any function continuous on and twice differentiable on (a, b). If for all and , then for any is greater than:
- (A)✓ Correct
- (B)
- (C)
- (D)1
Answer: (A)
Solution
Apply the mean value theorem on and on : and for some and . Since , the derivative is strictly decreasing, and gives , so . Because makes , rearranging yields .
JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Single correct option