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A secant or a cosecant beside a power of a sum of them is read as a power of the cosine or the sine - #1857

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a-secant-factor-read-as-a-power-of-the-cosine
Oct 12, 2026
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Rafael-SOWNet merged 3 commits into
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a-secant-factor-read-as-a-power-of-the-cosine

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Part of #718.

sec(x) sqrt(sec(x) + tan(x)) was declined, with the rest of Rubi's 4.7.7 that puts a secant or a cosecant beside a power of sec ± tan or csc ± cot. Two reads were missing:

  • SolveAsTheDerivativeOfAProductOfPowers took sec(x) as a function of its own, not cos(x)^(-1), so the integrand was never seen as (sec + tan)'-shaped. A secant or cosecant factor, or a constant power of one, is now read as the reciprocal power of the cosine or sine.
  • SolveByTangentSubstitution wrote an odd power of the secant through sqrt(1 + t^2) but not one of the cosecant, so sqrt(1 + tan(x)) csc(x) sec(x) stayed in x.
Input 2.5.0 master d21b783 this branch
sec(x)*sqrt(sec(x) + tan(x)) declined declined 2 * sqrt(sec(x) + tan(x))
sec(x)*sqrt(sec(x) - tan(x)) declined declined (-2) * sqrt(sec(x) - tan(x))
csc(x)*sqrt(csc(x) + cot(x)) declined declined (-2) * sqrt(csc(x) + cotan(x))
sec(a + b*x)*(sec(a + b*x) + tan(a + b*x))^c declined declined 1 / (b * c) * (sec(a + b * x) + tan(a + b * x)) ^ c
sqrt(1 + tan(x))*csc(x)*sec(x) declined declined 94 characters

Rubi corpus, branch against master b3805f8: one problem gained (4.7.7 #1125), none lost, 0 wrong in every family; the family-4 pocket gained two. Kernel gate and the full suite (15249 passed) pass.

🤖 Generated with Claude Code

https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

Rafael-SOWNet and others added 3 commits October 12, 2026 02:39
…e the other way up

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura
@Rafael-SOWNet Rafael-SOWNet added this to the 2.6.0 milestone Oct 12, 2026
@Rafael-SOWNet
Rafael-SOWNet merged commit a96bfa0 into master Oct 12, 2026
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Rafael-SOWNet deleted the a-secant-factor-read-as-a-power-of-the-cosine branch October 12, 2026 07:14
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