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Two linear factors whose product is a multiple of the radicand arsinh holds are written as that radicand - #1488

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(a + b arsinh(c x)) sqrt(d + i c d x) sqrt(f - i c f x) ran out of time. The two linear factors multiply to d f (1 + c^2 x^2), a constant multiple of the radicand that arsinh(c x) = ln(c x + sqrt(c^2 x^2 + 1)) holds. That is the case #1487 answers, spelled as two factors, and Rubi's 7.1.4 writes 72 of its 663 rows this way.

L1^p L2^q with p - q whole is now L1^(p - q) L1^q L2^q, and L1^q L2^q is lambda^q M^q for a whole q and K^k M^(k/2) for q = k/2, with K = sqrt(L1) sqrt(L2)/sqrt(M) carried as a symbol and written in front of the answer, constant wherever it is defined, as #1487's is. It is tried only where no single base is a multiple of the radicand, over the factors of both sides of the bar.

Measured

before after
(d + i c d x)^(5/2)(a + b arsinh(c x)) sqrt(f - i c f x) past 70 s 0.46 s
Rubi 7.1.4 + 7.1.5, all 376 problems that count 308 345, no row lost, 56 timeouts → 27
Rubi family 7 235/270 237/270
Rubi 7.2 files, families 1, 4, 5, 6 and the 1774-problem suite — unchanged, row for row
unit suite 12,698 12,704 (six cases added), 0 failed, run to completion
allocation gate — PASSED on all 19 gated benchmarks

The integrands are complex-valued along the whole line. Four of the shapes are exact at five points each compared as complex numbers, with a negative d among the pins, and the tests use numeric coefficients as well as symbolic ones. Still declined: the pair wholly below the bar, (a + b arsinh(c x))/((d + i c d x)^(5/2)(f - i c f x)^(3/2)), where the rewritten integral is the slow part.

Part of #718.

🤖 Generated with Claude Code

https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

… holds are written as that radicand

`(a + b arsinh(c x)) sqrt(d + i c d x) sqrt(f - i c f x)` ran out of time. The two linear
factors multiply to `d f (1 + c^2 x^2)`, a constant multiple of the radicand `arsinh(c x) =
ln(c x + sqrt(c^2 x^2 + 1))` holds -- the case #1487 answers, spelled as two factors. Rubi's
7.1.4 writes seventy-two of its 663 rows this way.

`L1^p L2^q` with `p - q` whole is now `L1^(p - q) L1^q L2^q`, and `L1^q L2^q` is `lambda^q M^q`
for a whole `q` and `K^k M^(k/2)` for `q = k/2`, with `K = sqrt(L1) sqrt(L2)/sqrt(M)` carried as
a symbol and written in front of the answer: constant wherever it is defined, as #1487's is.
Tried only where no single base is a multiple of the radicand, on the factors of both sides of
the bar, with a nested power read through and a factor below the bar read with its exponent
negated.

Rubi's 7.1.4 and 7.1.5, all 376 problems that count: 308 to 345, no row lost, 56 timeouts to
27. Family 7 235 to 237 of 270; the 7.2 files, families 1, 4, 5 and 6 and the 1774-problem suite
unchanged, row for row. The answers are complex-valued along the whole line and are exact at
five points each compared as complex numbers, with a negative `d` among the pins.

Part of #718.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
@Rafael-SOWNet
Rafael-SOWNet merged commit fa542e0 into master Sep 24, 2026
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Rafael-SOWNet added a commit that referenced this pull request Sep 24, 2026
arcsin(u) holds the radicand 1 - u^2 without writing it: its derivative
is u'/sqrt(1 - u^2). Beside arcsin(c x), the factors d + c d x and
f - c f x multiply to d f (1 - c^2 x^2), a multiple of that radicand.
The rule that writes such a multiple over the radicand (#1487, #1488)
took its radicands only from logarithms, so the pair ran out of time.

The radicand of an inverse sine or cosine of a linear is now one of the
radicands it reads. Two factors whose product is the radicand itself,
sqrt(1 + c x) sqrt(1 - c x), are written as its one root too.

Rubi's 5.1.4, 5.1.5, 5.2.4 and 5.2.5, all 504 problems that count:
405 to 463, no row lost, 77 timeouts to 19.


Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
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