∫Calc Practice

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

Problem 4.359 · easy

Find \( \displaystyle \int x^{2} \sin{\left(x \right)} \, dx \). (Omit the constant of integration.)
  1. \[ \int x^{2} \sin{\left(x \right)}\, dx \]
    integralStart with the integral of the integrand.✓ Proved
  2. \[ = - x^{2} \cos{\left(x \right)} - \int \left(- 2 x \cos{\left(x \right)}\right)\, dx \]
    partsApply integration by parts with u = x**2 and dv = sin(x) dx.✓ Proved
  3. \[ = - x^{2} \cos{\left(x \right)} + \int 2 x \cos{\left(x \right)}\, dx \]
    algebraSimplify the expression by distributing the negative sign.✓ Proved
  4. \[ = - x^{2} \cos{\left(x \right)} + 2 \int x \cos{\left(x \right)}\, dx \]
    linearityPull the constant 2 out of the integral.✓ Proved
  5. \[ = - x^{2} \cos{\left(x \right)} + 2 x \sin{\left(x \right)} - 2 \int \sin{\left(x \right)}\, dx \]
    parts algebraApply integration by parts again to the remaining integral with u = x and dv = cos(x) dx. Distribute the constant 2 into the parentheses.✓ Proved
  6. \[ = - x^{2} \cos{\left(x \right)} + 2 x \sin{\left(x \right)} + 2 \cos{\left(x \right)} \]
    antiderivative algebraEvaluate the integral of sin(x). Simplify the final expression.✓ Proved
Answer \( - x^{2} \cos{\left(x \right)} + 2 x \sin{\left(x \right)} + 2 \cos{\left(x \right)} + C \)

✓ 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
8✓ 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
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-05
  • gpt-oss:20b: pass 2026-10-05
  • qwen3.6:27b-mlx: pass 2026-10-05
  • gpt-oss:20b: pass 2026-10-05

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 2026-10-05 with SymPy 1.14.0.