Integral of \( \displaystyle 2 x + \left(x - 1\right)^{3} - 2 \)
Problem 4.279 · medium
Find \( \displaystyle \int 2 x + \left(x - 1\right)^{3} - 2 \, dx \). (Omit the constant of integration.)
- \[ \int \left(2 x + \left(x - 1\right)^{3} - 2\right)\, dx \]integralStart with the integral of the given expression.✓ Proved
- \[ = \int \left(x^{3} - 3 x^{2} + 5 x - 3\right)\, dx \]algebra simplifyExpand the binomial term (x - 1)**3. Combine like terms.✓ Proved
- \[ = - \int 3\, dx + \int 5 x\, dx - \int 3 x^{2}\, dx + \int x^{3}\, dx \]linearitySplit the integral into individual terms.✓ Proved
- \[ = \frac{x^{4}}{4} - x^{3} + \frac{5 x^{2}}{2} - 3 x \]antiderivativeIntegrate each term using the power rule.✓ Proved
Answer \( \frac{x \left(x - 2\right) \left(x^{2} - 2 x + 6\right)}{4} + C \)
✓ 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
| Line | Status | Checked by | Detail |
|---|---|---|---|
| 1 | ✓ Proved | sympy 1.14.0 | line 1 is the problem as stated |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated the stated antiderivative back to the integrand |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly expands the polynomial, combines like terms, applies linearity of integration, and computes the antiderivatives. The final result matches the stated answer.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-04 — The solution correctly expands the polynomial, combines like terms, applies linearity of integration, and computes the antiderivatives. The final result matches the stated answer.gpt-oss:20b: pass 2026-10-04qwen3.6:27b-mlx: pass 2026-10-04 — The solution correctly expands, simplifies, splits, and integrates the expression. Each step applies exactly one rule from the allowed vocabulary, and the labels are appropriate.gpt-oss:20b: pass 2026-10-04
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 2026-10-04 with SymPy 1.14.0.