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Home›Calculus 1›Product rule›Problem 2.1512

Derivative of \( \displaystyle - \frac{3 x^{2}}{2} - 2 x + \left(3 x^{2} + 4 x + \frac{4}{3}\right) \ln{\left(3 x + 2 \right)} \)

Problem 2.1512 · hard

Differentiate \( \displaystyle f(x) = - \frac{3 x^{2}}{2} - 2 x + \left(3 x^{2} + 4 x + \frac{4}{3}\right) \ln{\left(3 x + 2 \right)} \).
  1. \[ \frac{d}{d x} \left(- \frac{3 x^{2}}{2} - 2 x + \left(3 x^{2} + 4 x + \frac{4}{3}\right) \ln{\left(3 x + 2 \right)}\right) \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{3 x^{2}}{2}\right) + \frac{d}{d x} \left(3 x^{2} + 4 x + \frac{4}{3}\right) \ln{\left(3 x + 2 \right)} \]
    sumApply the sum rule to separate the terms.✓ Proved
  3. \[ = \left(3 x^{2} + 4 x + \frac{4}{3}\right) \frac{d}{d x} \ln{\left(3 x + 2 \right)} + \ln{\left(3 x + 2 \right)} \frac{d}{d x} \left(3 x^{2} + 4 x + \frac{4}{3}\right) - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{3 x^{2}}{2}\right) \]
    productApply the product rule to the third term.✓ Proved
  4. \[ = \left(6 x + 4\right) \ln{\left(3 x + 2 \right)} + \left(3 x^{2} + 4 x + \frac{4}{3}\right) \frac{d}{d x} \ln{\left(3 x + 2 \right)} - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{3 x^{2}}{2}\right) \]
    derivativeDifferentiate the polynomial part of the product.✓ Proved
  5. \[ = \left(6 x + 4\right) \ln{\left(3 x + 2 \right)} - \frac{d}{d x} 2 x + \frac{d}{d x} \left(- \frac{3 x^{2}}{2}\right) + \frac{3 \left(3 x^{2} + 4 x + \frac{4}{3}\right)}{3 x + 2} \]
    chain algebraApply the chain rule to the logarithm. Simplify the derivative of the log term.✓ Proved
  6. \[ = - 3 x + \left(6 x + 4\right) \ln{\left(3 x + 2 \right)} - 2 + \frac{3 \left(3 x^{2} + 4 x + \frac{4}{3}\right)}{3 x + 2} \]
    derivativeDifferentiate the remaining power terms.✓ Proved
  7. \[ = - 3 x + \left(6 x + 4\right) \ln{\left(3 x + 2 \right)} - 2 + \frac{9 x^{2} + 12 x + 4}{3 x + 2} \]
    algebraDistribute the 3 in the last term.✓ Proved
  8. \[ = \left(6 x + 4\right) \ln{\left(3 x + 2 \right)} \]
    algebra simplify simplifyRecognize the numerator as a perfect square. Simplify the fraction. Combine all remaining terms.✓ Proved
Answer \( 2 \left(3 x + 2\right) \ln{\left(3 x + 2 \right)} \)

✓ 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 3*x + 2 = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where 3*x + 2 = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where 3*x + 2 = 0
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where 3*x + 2 = 0
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where 3*x + 2 = 0
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
11✓ 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 and algebraic simplifications in a step-by-step manner. Each step adheres to the single-change constraint and uses valid labels from the fixed vocabulary.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-04 — The solution correctly applies differentiation rules and algebraic simplifications in a step-by-step manner. Each step adheres to the single-change constraint and uses valid labels from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-10-04
  • qwen3.6:27b-mlx: pass 2026-10-04 — The solution correctly applies differentiation rules step-by-step, adhering to the single-change constraint. The algebraic simplifications in the final steps are valid and clearly labeled.
  • 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.