Get Maxima to easily accept flag values

[kcrisman]

Maxima relatively recently decided that 1/sqrt(x) is not sqrt(1/x), for good reasons (1/sqrt(-1)=-i but sqrt(1/-1)=i in usual discussion). So for the following integral, they note that it depends on how you input it:

sage: integrate(sqrt(1/x^2+x),x)
integrate(sqrt(x + 1/x^2), x)
sage: integrate(1/sqrt(x^2+x),x)
log(2*x + 2*sqrt(x^2 + x) + 1)

Fine. Then they suggest using the flag radexpand:all to make the first one behave. But I can't figure out how to get it to evaluate.

sage: sage.calculus.calculus.maxima('radexpand:all')
all
sage: integrate(sqrt(1/x^2+x),x)
integrate(sqrt(x + 1/x^2), x)

Trying maxima.eval only changes that I get 'all' instead of all. We should make this work, since this is the calculus instance of Sage!

CC: @robert-marik @burcin @nbruin @jasongrout @wdjoyner

Component: calculus

Keywords: maxima, flag, radexpand

Author: Peter Bruin

Branch/Commit: b94b48a

Reviewer: Nils Bruin, Karl-Dieter Crisman

Issue created by migration from https://trac.sagemath.org/ticket/10955

[nbruin]

comment:1

Works for me on some flavour of 5.13.beta0

sage: integrate(sqrt(1/x^2+x),x)
integrate(sqrt(x + 1/x^2), x)
sage: sage.calculus.calculus.maxima('radexpand:all')
all
sage: integrate(sqrt(1/x^2+x),x)
2/3*sqrt(x^3 + 1) - 1/3*log(sqrt(x^3 + 1) + 1) + 1/3*log(sqrt(x^3 + 1) - 1)

I didn't check if the answer makes sense, but at least setting the flag has effect.

[pjbruin]

Author: Peter Bruin

[pjbruin]

Branch: u/pbruin/10955-maxima_radexpand

[pjbruin]

comment:2

Works for me too; here is a doctest.

[pjbruin]

Commit: b94b48a

[kcrisman]

Reviewer: Nils Bruin, Karl-Dieter Crisman, Michael Orlitzky

[kcrisman]

comment:3

As far as I can tell this is fine. I have no idea why this didn't work before. Passes tests, does right thing.

---

Wow, I am just now noticing that the suggestion made earlier was pretty bogus.

sage: integrate(1/sqrt(x^2+x),x)
log(2*x + 2*sqrt(x^2 + x) + 1)

Totally not the same thing as sqrt(1/x^2+x)! Should have been

sage: integrate(1/sqrt(x^2+x),x)
log(2*x + 2*sqrt(x^2 + x) + 1)
sage: integrate(sqrt(1/(x^2+x)),x)
log(sqrt(x + 1)/sqrt(x) + 1) - log(sqrt(x + 1)/sqrt(x) - 1)

which also happens to be affected by radexpand:all.

[kcrisman]

Changed reviewer from Nils Bruin, Karl-Dieter Crisman, Michael Orlitzky to Nils Bruin, Karl-Dieter Crisman

[vbraun]

Changed branch from u/pbruin/10955-maxima_radexpand to b94b48a