sympy/sympy — pull request #2184 by cheatiiit (2013-06-17 22:56:56+00:00)
Title: Hypertangent Extension Support for Structure Theorem 

This is still in implementation phase, In this Pr i have tried adding simple trigonometric functions of the form tan(x), which would call integrate_hypertangent_reduce and integrate_hypertangent_polynomial under method risch_integrate
To get this working i need coupledDifferntialSystem which still stands TODO