∫Calc Practice

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

Problem 4.874 · medium

Find \( \displaystyle \int 6 x + \left(3 x - 1\right)^{3} - 2 \, dx \). (Omit the constant of integration.)
  1. \[ \int \left(6 x + \left(3 x - 1\right)^{3} - 2\right)\, dx \]
    integral algebraStart with the integral of the given expression. Rearrange the terms for clarity.✓ Proved
  2. \[ = \int \left(3 x - 1\right)^{3}\, dx + \int \left(6 x - 2\right)\, dx \]
    linearitySplit the integral into two parts.✓ Proved
  3. \[ = 3 x^{2} - 2 x + \int \left(3 x - 1\right)^{3}\, dx \]
    antiderivativeIntegrate the polynomial part.✓ Proved
  4. \[ = 3 x^{2} - 2 x + \int \left(27 x^{3} - 27 x^{2} + 9 x - 1\right)\, dx \]
    algebraExpand the binomial term (3*x - 1)**3.✓ Proved
  5. \[ = \frac{27 x^{4}}{4} - 9 x^{3} + \frac{15 x^{2}}{2} - 3 x \]
    antiderivative simplifyIntegrate the expanded polynomial term. Combine all terms and simplify the expression.✓ Proved
Answer \( \frac{3 x \left(9 x^{3} - 12 x^{2} + 10 x - 4\right)}{4} + C \)

✓ 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
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
7✓ 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: pass — The solution correctly applies linearity, algebraic expansion, and antiderivative rules in separate steps. The final simplification is algebraically correct.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-11 — The solution correctly applies linearity, algebraic expansion, and antiderivative rules in separate steps. The final simplification is algebraically correct.
  • gpt-oss:20b: pass 2026-10-11
  • qwen3.6:27b-mlx: pass 2026-10-11 — The solution correctly applies linearity, algebraic expansion, and term-by-term integration. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-10-11

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 2026-10-11 with SymPy 1.14.0.