4844.sagews

f = exp(x) - 1

g = f.taylor(x,0,5)

g.reversion()

Traceback (most recent call last): File "<stdin>", line 1, in <module> File "_sage_input_4.py", line 10, in <module> exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("Zy5yZXZlcnNpb24oKQ=="),globals())+"\\n"); execfile(os.path.abspath("___code___.py"))' + '\n', '', 'single') File "", line 1, in <module> File "/tmp/tmpi9SLKn/___code___.py", line 2, in <module> exec compile(u'g.reversion()' + '\n', '', 'single') File "", line 1, in <module> File "element.pyx", line 332, in sage.structure.element.Element.__getattr__ (sage/structure/element.c:2920) File "parent.pyx", line 330, in sage.structure.parent.getattr_from_other_class (sage/structure/parent.c:3330) AttributeError: 'sage.symbolic.expression.Expression' object has no attribute 'reversion'

R.<x> = PowerSeriesRing(QQ)

f = exp(x) - 1

g = f.truncate_powerseries(5)

g.reversion()

x - 1/2*x^2 + 1/3*x^3 - 1/4*x^4 + O(x^5)