∫Calc Practice
Home›Calculus 1›Product rule›Problem 2.1600

Derivative of \( \displaystyle - \frac{x^{2}}{2} - 2 x + \left(x^{2} + 4 x + 4\right) \ln{\left(x + 2 \right)} \)

Problem 2.1600 · hard

Differentiate \( \displaystyle f(x) = - \frac{x^{2}}{2} - 2 x + \left(x^{2} + 4 x + 4\right) \ln{\left(x + 2 \right)} \).
  1. \[ \frac{d}{d x} \left(- \frac{x^{2}}{2} - 2 x + \left(x^{2} + 4 x + 4\right) \ln{\left(x + 2 \right)}\right) \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{d}{d x} \left(x^{2} + 4 x + 4\right) \ln{\left(x + 2 \right)} \]
    sumApply the sum rule.✓ Proved
  3. \[ = \left(x^{2} + 4 x + 4\right) \frac{d}{d x} \ln{\left(x + 2 \right)} + \ln{\left(x + 2 \right)} \frac{d}{d x} \left(x^{2} + 4 x + 4\right) - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) \]
    productApply the product rule to the third term.✓ Proved
  4. \[ = \left(2 x + 4\right) \ln{\left(x + 2 \right)} + \left(x^{2} + 4 x + 4\right) \frac{d}{d x} \ln{\left(x + 2 \right)} - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) \]
    derivativeDifferentiate the polynomial term.✓ Proved
  5. \[ = \left(2 x + 4\right) \ln{\left(x + 2 \right)} - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{x^{2} + 4 x + 4}{x + 2} \]
    derivativeDifferentiate the logarithm term.✓ Proved
  6. \[ = x + \left(2 x + 4\right) \ln{\left(x + 2 \right)} - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + 2 \]
    algebra algebraFactor the quadratic term. Simplify the fraction.✓ Proved
  7. \[ = \left(2 x + 4\right) \ln{\left(x + 2 \right)} \]
    derivative simplifyCompute the derivatives of the remaining terms. Combine like terms.✓ Proved
Answer \( 2 \left(x + 2\right) \ln{\left(x + 2 \right)} \)

✓ 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
log is undefined for non-positive arguments
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where x + 2 = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where x + 2 = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 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 f directly and got the stated answer

Reviewers

  • gpt-oss:20b: pass
  • qwen3.6:27b-mlx: pass — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. The labels accurately reflect the operations performed, and the final simplification is correct.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. The labels accurately reflect the operations performed, and the final simplification is correct.
  • gpt-oss:20b: pass 2026-10-05
  • qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly applies differentiation rules and algebraic simplifications. Each step changes only one aspect of the expression, and the labels accurately reflect the operations performed.
  • 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.