How to make TeXForm handle higher derivatives better.
See http://mathematica.stackexchange.com/questions/134936/texform-handling-of-derivative-higher-than-two
From above URL by Carl Woll
Derivative /: MakeBoxes[Derivative[n_Integer?Positive][h_],TraditionalForm] := SuperscriptBox[MakeBoxes[h,TraditionalForm], StringJoin@ConstantArray["\[Prime]",n] ] TeXForm[y'''''[t] + 2 x'''[t] - y'[t] == x[t]]