∫Calc Practice

Integral of \( \displaystyle 3 x - 1 + \frac{1}{3 x - 1} \)

Problem 4.552 · medium

Find \( \displaystyle \int 3 x - 1 + \frac{1}{3 x - 1} \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(3 x - 1 + \frac{1}{3 x - 1}\right)\, dx \]
    integralStart with the integral of the given function.✓ Proved
  2. \[ = - \int 1\, dx + \int 3 x\, dx + \int \frac{1}{3 x - 1}\, dx \]
    linearitySplit the integral into three parts.✓ Proved
  3. \[ = - \int 1\, dx + \int 3 x\, dx + \int \frac{1}{3 \left(x - \frac{1}{3}\right)}\, dx \]
    algebraRewrite the fraction using algebraic manipulation.✓ Proved
  4. \[ = - \int 1\, dx + \int 3 x\, dx + \frac{\int \frac{1}{x - \frac{1}{3}}\, dx}{3} \]
    linearityPull the constant factor out of the integral.✓ Proved
  5. \[ = \frac{3 x^{2}}{2} - x + \frac{\ln{\left(3 x - 1 \right)}}{3} \]
    antiderivativeCompute the antiderivative of each term.✓ Proved
Answer \( \frac{3 x^{2}}{2} - x + \frac{\ln{\left(3 x - 1 \right)}}{3} + C \)

✓ Nihil obstat 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. Reviewers found nothing wrong with the explanation.

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 3*x - 1 = 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where 3*x - 1 = 0
undefined where x - 1/3 = 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where x - 1/3 = 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where x - 1/3 = 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: pass
Every verdict on record (4)
  • gpt-oss:20b: pass 2026-10-07
  • qwen3.6:27b-mlx: pass 2026-10-07
  • qwen3.6:27b-mlx: pass 2026-10-07 — The solution correctly applies linearity to split the integral and factor out constants. The final antiderivative is computed correctly for each term.
  • gpt-oss:20b: pass 2026-10-07

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 2026-10-07 with SymPy 1.14.0.