f(x) / f'(x) puzzle
Enter a trial function f(x) that can depend on up to two parameters a and b.
The goal is to find a function such that the ratio of the function and its derivative is constant for all x.
If both x and f(x) are quantities rather than numbers [see "Semantic Aspects of Quantity" on the mathMINDhabits website] explain how and why this constant can be adjusted.