#3732: Unnecessary Maxima interactions in integration
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Reporter: was | Owner: gfurnish
Type: enhancement | Status: new
Priority: major | Milestone: sage-4.1.2
Component: calculus | Keywords:
Reviewer: | Author:
Merged: |
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Old description:
> These should be integrated into the doctest framework for sage's
> calculus. See attached. This is by Elliot Brossard.
New description:
Here are a variety of integrals for which Maxima should not have to
interact to ask about assumptions, but does.
--
Comment(by kcrisman):
Here is the current state of this ticket. Of the examples in the first
attached file, the following are legitimate bugs of this type.
The first example has unnecessary questions.
{{{
sage: integrate(1/sqrt(x-q), x, 1, 2)
2 sqrt(2 - q) - 2 sqrt(1 - q) # should be this always
}}}
The third example is definitely a case for this, as of Maxima 5.19.1:
{{{
(%i19) integrate(log(q-x), x, a, b);
Is b - a positive, negative, or zero?
positive;
(%o19) (b - q) log(q - b) - (a - q) log(q - a) - b + a
(%i20) integrate(log(q-x), x, a, b);
Is b - a positive, negative, or zero?
negative;
(%o20) (b - q) log(q - b) - (a - q) log(q - a) - b + a
(%i21) integrate(log(q-x), x, a, b);
Is b - a positive, negative, or zero?
zero;
(%o21) (b - q) log(q - b) - (a - q) log(q - a) - b + a
}}}
The fifth example has MANY questions to ask, always the same answer:
{{{
(%i36) integrate(1/sqrt(q^2-x^2),x, a, b);
Is b - a positive, negative, or zero?
negative;
Is q - a positive, negative, or zero?
zero;
Is q + a positive, negative, or zero?
zero;
Is q + b positive, negative, or zero?
positive;
b a
(%o36) asin(------) - asin(------)
abs(q) abs(q)
}}}
++++++++++++++++++++++++++++++++
The following should not be considered bugs, at least not for the reason
given.
The second example is okay:
{{{
sage: integrate(1/(x-q),x,1,2)
}}}
Maxima adds pi*I and/or switches q-2 to 2-q as appropriate. If we don't
like those differences, that should be on a different ticket.
The fourth example is:
{{{
sage: integrate(1/(q-x^2), x)
}}}
The answers given are a constant away from each other, but look very
different. This probably should be considered a bug (Maxima can't connect
between logs and arctan/h stuff), but is likely to not be resolved soon,
or by questions.
The last example is definitely not a bug, as for q=-1 you should get a
different answer!
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/3732#comment:5>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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