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Integrate a power of x beside a binomial in an odd negative power of x on both sides of 0 - #2038

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binomial-in-a-negative-power-real-on-both-sides
Oct 22, 2026
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Part of #233.

  • A power of x beside a binomial in an odd negative power of x, on both sides of 0. SolveByTakingAPowerOfXOutOfAFractionalPower takes x^(j p) out of a sum of whole powers of x under a fractional power p. For sqrt(a + b/x^3)/x it wrote x^(-3/2) sqrt(a x^3 + b), which has no value at a negative x, where a + b/x^3 is real. So fourteen of Rubi's 1.1.3.2 x^m (a + b/x^3)^(k/2) were answered for a positive x only. Past an odd j other than 1 and -1, where j p is not whole, the rule now declines. The substitution in the root answers them on both sides: sqrt(a + b/x^3)/x is a function of u = sqrt(a + b/x^3).
  • Where j p is whole, the rule is kept. There x^(j p) is real on both sides: (a x^3 + b x^6)^(5/3), Rubi's 1.2.3.2, is x^5 times a power of a + b x^3. The first version of the guard keyed on the odd power alone and lost that row. A test pins it now.

Chain against master 2a98be4:

  • The pocket of 3,987 rows went from 3,950 to 3,964 solved, with 0 wrong.
  • Every family's sample is unchanged.
  • The 14 rows that moved, run alone, went from 14 partial to 14 solved.
  • No row's allocation grew past 1.3x and 300 MB; the largest growth was 0.02 GB.

The full unit suite passes locally: 16,462 passed, 0 failed. The BREAKING-CHANGES lengths were measured on the branch. Rebased onto 78cd31b, keeping both entries where the BREAKING-CHANGES anchors met.

🤖 Generated with Claude Code

https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

…x on both sides of 0

SolveByTakingAPowerOfXOutOfAFractionalPower took x^(j p) out of a sum of
whole powers of x under a fractional power p: for sqrt(a + b/x^3)/x it wrote
x^(-3/2) sqrt(a x^3 + b), which has no value at a negative x, where
a + b/x^3 is real, and fourteen of Rubi's 1.1.3.2 x^m (a + b/x^3)^(k/2) were
answered for a positive x only. Past an odd j other than 1 and -1, where j p
is not whole, the rule now declines, and the substitution in the root answers
them on both sides: sqrt(a + b/x^3)/x is a function of u = sqrt(a + b/x^3).
Where j p is whole, x^(j p) is real on both sides and the rule is kept:
(a x^3 + b x^6)^(5/3), Rubi's 1.2.3.2, is x^5 times a power of a + b x^3.

Chain against master 2a98be4: the 14 partial answers of 1.1.3.2 are solved
on both sides, and the first version's guard, on the odd power alone, lost
1.2.3.2:8; keyed on j p it is answered again, 15 of 15 alone in the probe.

Part of #233.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
@Rafael-SOWNet
Rafael-SOWNet force-pushed the binomial-in-a-negative-power-real-on-both-sides branch from a7e9580 to 20353a8 Compare October 22, 2026 00:15
@Rafael-SOWNet
Rafael-SOWNet merged commit dd4ebcb into master Oct 22, 2026
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@github-project-automation github-project-automation Bot moved this from Todo to Done in AngouriMath Oct 22, 2026
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