Hello, Jeremy. Try this: from sympy.simplify.fu import TR7
TR7(cos(x)**2) On Friday, March 27, 2015 at 8:36:43 PM UTC+2, Jeremy Holleman wrote: > > Hi, > > I'm relatively new to SymPy, and enjoying it so far. I'm trying to > analyze the harmonics that result when a sinusoid goes through a non-linear > system. I have an expression that includes powers of a cos() and I want to > expand it using the sum/difference angle identities. So I want > > In [5]: some_function(cos(x)**2) > Out[5]: 1/2 + cos(2*x) > > But I'm getting > In [5]: expand_trig(cos(x)**2) > Out[5]: cos(x)**2 > > I've tried expand_trig(), trigsimp(), expand() (with several different > sets of hints), simplify(), and http://www.sympygamma.com/ and they all > just return the same expression that I've given them. Any ideas would be > much appreciated. > > Thanks, > Jeremy > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/4e65ad0a-9b10-42ca-9dae-8b8c45b98ab7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.