Home›Calculus 1›Derivatives and integrals of hyperbolic functions›Problem 2.2238

Derivatives and integrals of hyperbolic functions

Problem 2.2238 · medium

Find \( \displaystyle \int \cosh{\left(3 x + 3 \right)} \, dx \). (Omit the constant of integration.)

Use (cosh u)′ = sinh u, (sinh u)′ = cosh u, (tanh u)′ = sech²u, with a substitution for the inside.
Reviewed
\[ \frac{d}{d x} \frac{\sinh{\left(3 x + 3 \right)}}{3} = \cosh{\left(3 x + 3 \right)} \]
Differentiating the answer returns the integrand.✓ Proved

Answer \( \frac{\sinh{\left(3 x + 3 \right)}}{3} + C \)

✓ Nihil obstat Lines: 1 proved, 1 reviewed. The answer was also checked a second way, without looking at the solution. Reviewers found nothing wrong with the explanation. How we verify

The full receipt

Line	Status	Checked by	Detail
1	Reviewed	reviewers: gpt-oss:20b, qwen3.6:27b-mlx	a sentence; read, not computed
2	✓ Proved	sympy 1.14.0	simplify(lhs - rhs) reduced to 0
answer, a second way	✓ Checked independently	sympy 1.14.0 + mpmath 1.3.0	a central difference, with sinh and cosh computed from exponentials by mpmath

Reviewers

gpt-oss:20b: pass
qwen3.6:27b-mlx: pass — The solution correctly identifies the integration rule for hyperbolic cosine and applies the chain rule via substitution. The verification step confirms the result.

Every verdict on record (6)

qwen3.6:27b-mlx: pass 2026-10-17 — The solution correctly identifies the integration rule for hyperbolic cosine and applies the chain rule via substitution. The verification step confirms the result.
gpt-oss:20b: pass 2026-10-17
qwen3.6:27b-mlx: pass 2026-10-14 — The solution correctly identifies the integration rule for hyperbolic cosine and verifies the result by differentiation. The omission of the constant of integration in the final answer matches the problem statement.
gpt-oss:20b: pass 2026-10-14
qwen3.6:27b-mlx: pass 2026-10-14 — The solution correctly identifies the integration rule for cosh and applies the chain rule (substitution) properly. The verification step confirms the result.
gpt-oss:20b: pass 2026-10-14

Proved: SymPy reduced the difference between the two sides to zero. Checked independently: a separate method, named above, confirmed it. Checked numerically: the two sides agree at every sampled point, which is evidence, not proof. Reviewed: a model or a person read it; that is all a sentence can have. Solution by generator:structured/hyperbolic_calculus, checked 2026-10-17 with SymPy 1.14.0.