If is a real-valued differentiable function satisfying and , then equals
- (A)
- (B)✓ Correct
- (C)
- (D)
Answer: (B)
Solution
For , dividing by gives . Letting , the right-hand side tends to , which forces at every point. Thus is constant, and since we have for all , so .
JEE Main · 2005 · 08 May 2005 · Offline · Single correct option