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Integral of \( \displaystyle e^{2 x + 1} \sin{\left(e^{2 x + 1} \right)} \)

Problem 4.798 · medium

Find \( \displaystyle \int e^{2 x + 1} \sin{\left(e^{2 x + 1} \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int e^{2 x + 1} \sin{\left(e^{2 x + 1} \right)}\, dx \]
    integral algebraStart with the integral of the given function. Multiply and divide by 2 to prepare for substitution.✓ Proved
  2. \[ = \int \frac{\sin{\left(e^{2 x + 1} \right)} \frac{d}{d x} e^{2 x + 1}}{2}\, dx \]
    rewriteExpress the integrand in terms of the derivative of the inner function.✓ Proved
  3. \[ = \int e^{2 x + 1} \sin{\left(e^{2 x + 1} \right)}\, dx \]
    simplify simplifyCalculate the derivative of the inner function. Simplify the expression inside the integral.✓ Proved
  4. \[ = - \frac{\cos{\left(e^{2 x + 1} \right)}}{2} \]
    antiderivativeIntegrate using the substitution u = exp(2*x + 1).✓ Proved
Answer \( - \frac{\cos{\left(e^{2 x + 1} \right)}}{2} + C \)

Every line of this solution was proved by the computer algebra system SymPy. The answer was also checked a second way, without looking at the solution. The reviewers disagree about how one step is explained; every verdict is in the receipt.

The full receipt
LineStatusChecked byDetail
1✓ Provedsympy 1.14.0line 1 is the problem as stated
2✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
answer, a second way✓ Provedsympy 1.14.0SymPy differentiated the stated antiderivative back to the integrand

Reviewers

  • gpt-oss:20b: pass
  • qwen3.6:27b-mlx: fail (error) — Step 4 incorrectly labels the calculation of a derivative as 'simplify'. Step 5 is a logical error that undoes the previous work, returning to the original integral, which breaks the 'one change per step' rule and makes the subsequent jump to the answer in Step 6 unjustified.
Every verdict on record (4)
  • gpt-oss:20b: pass 2026-10-10
  • qwen3.6:27b-mlx: fail (error) 2026-10-10 — Step 4 incorrectly labels the calculation of a derivative as 'simplify'. Step 5 is a logical error that undoes the previous work, returning to the original integral, which breaks the 'one change per step' rule and makes the subsequent jump to the answer in Step 6 unjustified.
  • qwen3.6:27b-mlx: fail (error) 2026-10-10 — Steps 4 and 5 create a logical loop that undoes the preparation in Step 2, returning to the original integral without performing the substitution. Step 6 then claims to integrate using substitution, but the preceding steps did not execute the substitution (changing variables from x to u), making the transition from Step 5 to Step 6 invalid as a single step.
  • gpt-oss:20b: pass 2026-10-10

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 gemma4:26b, checked 2026-10-10 with SymPy 1.14.0.