I believe it will be possible to extend the algorithm at https://github.com/sympy/sympy/pull/1258 to handle expressions like these.
Aaron Meurer On Sat, Oct 27, 2012 at 12:32 AM, Chris Smith <[email protected]> wrote: > In my github branch, smichr/trigsimp there was some work added to > handle these...that branch is not being maintained and is far behind > the master branch but perhaps it would be of use: > >>>> eq > sin(a)*cos(b) - sin(b)*cos(a) >>>> simplify(eq) > sin(a - b) > > In that branch however, the simplified expression does not > expand...and if you do things to make it expand it doesn't go back to > the simplest formula again > > >>>> sin(a-b).rewrite(tan) > 2*tan(a/2 - b/2)/(tan(a/2 - b/2)**2 + 1) >>>> simplify(_) > 2*cos(a/2 - b/2)**2*tan(a/2 - b/2) > > > YMMV, > Chris > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
