In the good old days Mathcad used Maple for its symbolic calculations and as you could see in Luc's post (with MC11 and Maple) Maple is able to find all solutions.
More than ten years ago Maple was replaced by MuPad and this was a big step backward. When Maple is not able to find an exact solution it switches to its own numeric mode and returns the first solution found. Modifiers like "solve, fully" or "assume,t>5" have no effect.
But it gets even worse: With Prime 6 PTC has introduced a new symbolic engine (in P6 you still can switch back to MuPad but in later Versions this will not be possible) and if you feed this engine with your problem, it calculates forever (I stopped it after two hours) and does not come up with a single solution.
So if you need other solutions than the one the symbolic is returning, you have to resort to Mathcads numeric methods (solve block or the root command) where you have more control by providing different guesses or a different range for root to look for.
