f(x) = f(x0) + (x-x0)*f(x).diff(x)|x=x0 + .... Is there any reason not to allow that rhs as the return for >>> f(x).series(x) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "sympy\core\expr.py", line 2341, in series s = self.subs(x, rep).series(x, x0=0, n=n, dir='+') File "sympy\core\expr.py", line 2354, in series s1 = self._eval_nseries(x, n=n, logx=None) File "sympy\core\function.py", line 447, in _eval_nseries supported.''')) NotImplementedError: series for user-defined functions are not supported.
Maybe it could return something like this: >>> def fseries(eq, x0, n): ... return Add(*[(x - x0)**i*Subs(eq.diff(x, i), x, x0) for i in range(n + 1)]) >>> pprint(fseries(f(x), 1, 2).doit()) / 2 \| 2 | d || /d \| (x - 1) *|---(f(x))|| + (x - 1)*|--(f(x))|| + f(1) | 2 || \dx /|x=1 \dx /|x=1 -- 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?hl=en. For more options, visit https://groups.google.com/groups/opt_out.