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Read half-odd powers of a hyperbolic sine beside an exponential as a derivative - #2054

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read-half-odd-powers-of-a-hyperbolic-sine-beside-an-exponential-as-a-derivative
Oct 22, 2026
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read-half-odd-powers-of-a-hyperbolic-sine-beside-an-exponential-as-a-derivative

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Part of #233.

  • Half-odd powers of a hyperbolic sine beside an exponential, read as a derivative. Rubi's 6.7.1 e^(a + b x) sinh(c + d x)^(3/2) - 3/4 e^(a + b x) d^2/((b^2 - 9/4 d^2) sqrt(sinh(c + d x))) was declined. Each term alone is not elementary, and the sum is the derivative of e^(a + b x) (4 b sinh^(3/2) - 6 d cosh sinh^(1/2))/(4 b^2 - 9 d^2).
  • The ansatz. Write E = e^(a + b x), S = sinh(u), C = cosh(u) and u = c + d x. Then (E S^p C^q)' = E (b S^p C^q + d p S^(p - 1) C^(q + 1) + d q S^(p + 1) C^(q - 1)), with C^2 = 1 + S^2. So the answer is a sum of E S^p C^q over the integrand's monomials and the partners their derivative reaches, and its coefficients are a linear system.
  • Solving it. The system is square, one row per monomial of the ansatz. Each compound coefficient of the integrand is named while it is solved. Without that, the symbolic elimination reduced a row to 0 = c, where c is zero only as a value, and declined.
  • Branches. Powers of one sine multiply on every branch, and no power of a power is taken. The rule is last in the dispatch, and the answer is checked by its derivative.
Input master ef4150e this branch
6.7.1:1141 declined 249 characters, e^(a + b x) (4 b S^(3/2) - 6 d S^(1/2) C)/(4 b^2 - 9 d^2)

Chain against master ef4150e (the branch rebased onto 7d1081e):

The library builds for netstandard2.0, net8.0 and net10.0. The suite is left to CI. The BREAKING-CHANGES length was measured on the branch, and the 2.5.0 column on a v2.5.0 build.

🤖 Generated with Claude Code

https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura

…derivative

Rubi's 6.7.1 e^(a + b x) sinh(c + d x)^(3/2) - 3/4 e^(a + b x) d^2/
((b^2 - 9/4 d^2) sqrt(sinh(c + d x))) was declined: each term alone is not
elementary, and the sum is the derivative of
e^(a + b x) (4 b sinh^(3/2) - 6 d cosh sinh^(1/2))/(4 b^2 - 9 d^2). With
E = e^(a + b x), S = sinh(u), C = cosh(u), u = c + d x,
(E S^p C^q)' = E (b S^p C^q + d p S^(p - 1) C^(q + 1) + d q S^(p + 1) C^(q - 1))
with C^2 = 1 + S^2, so the answer is a sum of E S^p C^q over the integrand's
monomials and the partners their derivative reaches, and its coefficients
are a linear system: square, one row per monomial of the ansatz, with each
compound coefficient of the integrand named while it is solved, since the
elimination with symbols declined a row reducing to a zero it could not
decide. Powers of one sine multiply on every branch, and no power of a power
is taken. Last in the dispatch; checked by its derivative.

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 added this to the 2.6.0 milestone Oct 22, 2026
@Rafael-SOWNet
Rafael-SOWNet merged commit 1566841 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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