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Integral of \( \displaystyle \frac{1}{6 x + \left(2 x - 1\right)^{2} - 3} \)

Problem 4.997 · medium

Find \( \displaystyle \int \frac{1}{6 x + \left(2 x - 1\right)^{2} - 3} \, dx \). (Omit the constant of integration.)
  1. \[ \int \frac{1}{6 x + \left(2 x - 1\right)^{2} - 3}\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = \int \frac{1}{4 x^{2} + 2 x - 2}\, dx \]
    algebra algebra algebraExpand the squared term. Combine like terms. Factor out the constant 2.✓ Proved
  3. \[ = \int \frac{1}{\left(x + 1\right) \left(4 x - 2\right)}\, dx \]
    algebra algebraFactor the quadratic expression. Factor out 2 from the first linear term to simplify the fraction.✓ Proved
  4. \[ = \int \left(- \frac{1}{6 x + 6} + \frac{1}{6 x - 3}\right)\, dx \]
    partial-fractionsDecompose the integrand using partial fractions.✓ Proved
  5. \[ = \int \frac{1}{6 x - 3}\, dx - \int \frac{1}{6 x + 6}\, dx \]
    linearitySplit the integral into two parts.≈ Checked numerically
  6. \[ = \frac{\ln{\left(x - \frac{1}{2} \right)}}{6} - \frac{\ln{\left(x + 1 \right)}}{6} \]
    antiderivativeEvaluate the integrals using the natural logarithm rule.≈ Checked numerically
Answer \( \frac{\ln{\left(x - \frac{1}{2} \right)} - \ln{\left(x + 1 \right)}}{6} + C \)

Lines: 8 proved, 2 checked numerically. 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
undefined where 6*x + (2*x - 1)**2 - 3 = 0
undefined where 4*x**2 + 2*x - 2 = 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where 4*x**2 + 2*x - 2 = 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where 4*x**2 + 2*x - 2 = 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where 4*x**2 + 2*x - 2 = 0
undefined where x + 1 = 0
undefined where 4*x - 2 = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where x + 1 = 0
undefined where 4*x - 2 = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where x + 1 = 0
undefined where 4*x - 2 = 0
undefined where 6*x - 3 = 0
undefined where 6*x + 6 = 0
8≈ Checked numericallysympy 1.14.0sympy 1.14.0: simplify left log(x - 1/2)/6 - log(2*x - 1)/6 - log(3)/6 + log(6)/6; numeric agreement only, at 24 of 24 sampled points
undefined where 6*x - 3 = 0
undefined where 6*x + 6 = 0
9≈ Checked numericallysympy 1.14.0sympy 1.14.0: simplify left -log(x - 1/2)/6 + log(2*x - 1)/6 - log(6)/6 + log(3)/6; numeric agreement only, at 24 of 24 sampled points
undefined where 6*x - 3 = 0
undefined where 6*x + 6 = 0
log is undefined for non-positive arguments
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
log is undefined for non-positive arguments
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 7 is algebraically incorrect; the partial fraction decomposition of 1/(4*(x - 1/2)*(x + 1)) yields 1/(6*(x - 1/2)) - 1/(3*(x + 1)), not 1/(6*(x - 1/2)) - 1/(6*(x + 1)). This leads to an incorrect final answer.
Every verdict on record (4)
  • gpt-oss:20b: pass 2026-10-13
  • qwen3.6:27b-mlx: fail (error) 2026-10-13 — Step 7 is algebraically incorrect; the partial fraction decomposition of 1/(4*(x - 1/2)*(x + 1)) yields 1/(6*(x - 1/2)) - 1/(3*(x + 1)), not 1/(6*(x - 1/2)) - 1/(6*(x + 1)). This leads to an incorrect final answer.
  • gpt-oss:20b: pass 2026-10-13
  • qwen3.6:27b-mlx: pass 2026-10-13 — The solution correctly expands, factors, and decomposes the integrand. Each step applies a single rule from the allowed vocabulary, and the labels are accurate.

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 2026-10-13 with SymPy 1.14.0.