#16197: provide function expansions of power series (from Pari)
---------------------------+----------------------------------------------
   Reporter:  rws          |            Owner:
       Type:  enhancement  |           Status:  new
   Priority:  major        |        Milestone:  sage-6.2
  Component:  calculus     |         Keywords:  function, series expansion
  Merged in:               |          Authors:
  Reviewers:               |  Report Upstream:  N/A
Work issues:               |           Branch:
     Commit:               |     Dependencies:
   Stopgaps:               |
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 Not the same as `SR.taylor()`.
 {{{
 sage: R.<x> = PowerSeriesRing(ZZ)
 sage: sqrt(1-4*x^2)
 1 - 2*x^2 - 2*x^4 - 4*x^6 - 10*x^8 - 28*x^10 - 84*x^12 - 264*x^14 -
 858*x^16 - 2860*x^18 + O(x^20)
 sage: sin(1+4*x^2)
 ...
 TypeError: cannot coerce arguments: no canonical coercion from Power
 Series Ring in x over Integer Ring to Symbolic Ring
 sage: var('X')
 X
 sage: ex=sin(1+4*X^2)
 sage: ex.series()
 ...
 TypeError: series() takes exactly 2 positional arguments (0 given)
 }}}
 What is missing and can be had from Pari:
 * `acos`, `acosh`, `agm`, `asin`, `asinh`, `atan`, `atanh`, `cos`, `cosh`,
 `cotanh`, `dilog`, `gamma`, `intformal`, `lngamma`, `psi`, `sin`, `sinh`,
 `tan`, `tanh`
 For example:
 {{{
 ? atan(4*x^2+1)
 %1 = 0.78539816339744830961566084581987572105 + 2*x^2 - 4*x^4 + 16/3*x^6 -
 128/5*x^10 + 256/3*x^12 - 1024/7*x^14 + O(x^16)
 }}}

--
Ticket URL: <http://trac.sagemath.org/ticket/16197>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
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