This question already has an answer here:
There exists a question which looks interesting to me, given that I scribbled some attempts to solve it and, in spite of the fact that it "seems" like an easy application of Rolle's theorem, couldn't solve.
So I'd like to see it answered to understand what I missed and should have done.
But the question is closed (rightfully, in my opinion), as the original poster did not provide any effort nor context.
What is the best way to see the question answered? Vote for its reopening (but on what grounds, as it violates the guidelines)? Create a duplicate (with pointer) where I provide my own efforts? Something else?