> > diff --git a/sympy/functions/elementary/exponential.py b/sympy/functions= /elementary/exponential.py > > --- a/sympy/functions/elementary/exponential.py > > +++ b/sympy/functions/elementary/exponential.py > > @@ -13,7 +13,7 @@ class exp(Function): > > raise ArgumentIndexError(self, argindex) > > > > def inverse(self, argindex=3D1): > > - return S.Log > > + return log > > > > @classmethod > > def _eval_apply_subs(self, *args): > > @@ -124,7 +124,7 @@ class exp(Function): > > arg =3D self.args[0] > > o =3D old > > if isinstance(old, Basic.Pow): # handle (exp(3*log(x))).subs(x*= 2, z) -> z*(3/2) > > - old =3D exp(old.exp * S.Log(old.base)) > > + old =3D exp(old.exp * log(old.base)) > > if isinstance(old, exp): > > b,e =3D self.as_base_exp() > > bo,eo =3D old.as_base_exp() >=20 > I would suggest to either write tests, or remove the code. >=20 > But yes, this patch can go in, but unless there are tests for this, I > don't see any point of having such a code.

It seems this piece of code is never (?) executed in sympy since exp(3*log(x)) canonize to x**3.

On the other hand when autoevaluation would be turned off exp(3*log(x)) will be just that -- so there should be a test which constructs unevaluated exp(3*log(x)) and calls subs.

I'm not sure how to do it now, please advise.

exp(3*log(x),evaluate=False) exp(3*log(x))

This was rather confusing to the Code-In student who is doing it. In the future, to be very explicit about what needs to be done if you add the CodeIn labels to an issue.

This was fixed. See https://github.com/sympy/sympy/pull/733.

We have moved issues to GitHub https://github.com/sympy/sympy/issues.

Migrated to http://github.com/sympy/sympy/issues/3753