The brachistochrone is a well-known problem in calculus of variations and optimal control. I ask if there is any explicit solution to the problem?. In the existing texts, x and y are usually parameterized in dummy variables as t, phi or theta. I want to know whether any explicit solution is available or not? I mean y(x) in terms of x, not any other intermediary variable.
In the pdf, attached to this question, there is some hint on the explicit solution (but it seems it is computational and numerical).
https://en.wikipedia.org/wiki/Brachistochrone_curve
http://mathworld.wolfram.com/BrachistochroneProblem.html