substitution example generates error

[eeshugerman]

http://www.sympy.org/en/features.html, under 'Core capabilities', the example link for 'Substitution' opens SymPy Gamma and evaluates an expression which gives an error.

[thomasaarholt]

I came to report this as well. The example is listed as
(exp(x) / (1 + exp(2x))).subs(exp(x), u), with the error can't multiply sequence by non-int of type 'instancemethod'. When I try running this on my own system, I get a syntax error, since the 2x should be 2*x. Fixing the multiplication, it runs fine locally, but still gives an error on the website.

[shubhamachary56821]

Hi there, I would be glad to work on this issue, could You please assign me?

[thomasaarholt]

This is an eight year old issue. I would just make a PR if I were you. Assigning makes sense where multiple people might do the same work unless it is communicated.

[oscarbenjamin]

Generally I thought we stopped maintaining SymPy Gamma. There is also now SymPy Beta although that seems out of date.
SymPy Live is what is kept up to date and should most likely be used for these kinds of examples.