sympy/sympy — pull request #2551 by ppuedom (2013-10-26 18:16:31+00:00)
Title: issue 1475: Add missing functions to  sec() and csc()

Previous implementation of csc() and sec() was missing most of the methods
required to work with simplify(), eval(), rewrite(), series().
This implementation reuses partly the implementation of the functions in
sin() and cos(). This is done through an intermediate base class
ReciprocalTrigonometricFunction which csc and sec now subclass.