And, of course, there's always the expr.rewrite(exp).expand().powsimp().rewrite(sin).expand() trick.
Aaron Meurer On Sat, Oct 27, 2012 at 1:04 AM, Aaron Meurer <[email protected]> wrote: > 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.
