From 776b71d758fe3724b98e59061711877e04849092 Mon Sep 17 00:00:00 2001 From: Sergey B Kirpichev Date: Sun, 6 Dec 2015 17:37:49 +0300 Subject: [PATCH] XXX fix expansion for f0 in (S.Zero, S.Infinity, S.NegativeInfinity) --- sympy/core/power.py | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/sympy/core/power.py b/sympy/core/power.py index 47d6030a63..73f0b3e6de 100644 --- a/sympy/core/power.py +++ b/sympy/core/power.py @@ -1265,9 +1265,11 @@ def _taylor(expr, x, n): f0 = b.limit(x, 0) a = e - if f0 is S.Zero: + if f0 in (S.Zero, S.Infinity, S.NegativeInfinity): lt = b.as_leading_term(x) - return lt**a*((b/lt)*a)._eval_nseries(x, n, logx) + if f0 == S.NegativeInfinity: + lt = -lt + return (lt**a*((b/lt).expand(mul=True)**a)._eval_nseries(x, n, logx)).expand(mul=True) from sympy.functions.combinatorial.factorials import factorial, binomial from sympy.functions.elementary.complexes import arg