Am 01.06.2016 um 04:56 schrieb oldk1331: > Yes, you are right, I've fixed symFunc to match its description. > > The next problem is to fix TANEXP accordingly, which I'll do > later. But now is the problem of document it: > > Take tanPIa for example, tanPIa returns a FRAC SUPR, > which has this property: > > tan(n*x)=tanPIa(n)(tan x) > > tanNa is a wrapper of tanPIa, you can try 'tanNa(tan x, 5)' > in interpreter. > > aka, tanPIa expands tan(n*x) into a fraction of polynomial > of tan(x), strangely, I can't find a webpage describing the > algorithm used in fricas, I can only find a recursive algorithm. > (although I didn't spend much time googling it) >
It's probably this one: https://en.wikipedia.org/wiki/List_of_trigonometric_identities#Tangents_of_sums There is a reference [15]: Bronstein, Manuel (1989). "Simplification of real elementary functions". In G. H. Gonnet (ed.). Proceedings of the ACM-SIGSAM 1989 International Symposium on Symbolic and Algebraic Computation. ISSAC'89 (Portland US-OR, 1989-07). New York: ACM. pp. 207–211. doi:10.1145/74540.74566. ISBN 0-89791-325-6. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to fricas-devel+unsubscr...@googlegroups.com. To post to this group, send email to fricas-devel@googlegroups.com. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
