/*
Copyright (C) 2021 Daniel Schultz
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
/*
if f is continuous with
f(0) = 0
f'(x) = alpha for 0 < x < a
f'(x) = beta for a < x < a + b
return solution for x to f(x) = (a*alpha + b*beta)*yn/yd
for 0 <= yn/yd <= 1
*/
ulong