Date: Jul 16, 2013 4:05 AM
Author: daly@axiom-developer.org
Subject: Re: An independent integration test suite

On Tuesday, July 16, 2013 4:00:13 AM UTC-4, da...@axiom-developer.org wrote:
> On Tuesday, July 16, 2013 2:19:26 AM UTC-4, Albert Rich wrote:
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> > On Monday, July 15, 2013 9:36:04 AM UTC-10, da...@axiom-developer.org wrote:
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> > > In order to ensure that the answers of the integration differ by no
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> > > more than a constant I've been differencing the expected answer from
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> > > the Axiom answer and then taking the derivative.
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> > > One curious pattern is that your answers differ from Axiom's answers
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> > > by non-zero constants. [...]
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> > The first sentence above correctly asserts that it is ok for antiderivatives to differ by a constant. Yet, the second sentence finds it surprising that they do differ. So what is the problem?
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> > Albert
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> suppose
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> t0:= expression
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> r0:= expected result
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> a0:= integrate(t0,x)
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> m0:= a0 - r0
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> d0:= differentiate(m0,x)
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> m0 is the difference between Axiom's result and the expected result.
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> d0 is the derivative of m0, usually with a value of 0.
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> m0 often shows that Axiom's result and the expected result differ
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> and the derivative result of 0 shows that this is just a constant.
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> When I look at the reason for the constant difference it seems to be
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> related to the trig identities we chose. What system did you use to
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> create the expected results?


That last was just a dumb question... you used Rubi, no doubt.
What I wanted to ask was what trig substitutions you use.
Is there somewhere in the Rubi sources I should look?