∫Calc Practice

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

Problem 2.614 · hard

Differentiate \( \displaystyle f(x) = \left(x - 3\right)^{2} \ln{\left(x - 3 \right)} \).
  1. \[ \frac{d}{d x} \left(x - 3\right)^{2} \ln{\left(x - 3 \right)} \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \left(x - 3\right)^{2} \frac{d}{d x} \ln{\left(x - 3 \right)} + \ln{\left(x - 3 \right)} \frac{d}{d x} \left(x - 3\right)^{2} \]
    productApply the product rule.✓ Proved
  3. \[ = \left(x - 3\right)^{2} \frac{d}{d x} \ln{\left(x - 3 \right)} + \left(2 x - 6\right) \ln{\left(x - 3 \right)} \]
    powerDifferentiate the first part using the power rule.✓ Proved
  4. \[ = x + \left(2 x - 6\right) \ln{\left(x - 3 \right)} - 3 \]
    logarithmic algebraDifferentiate the natural logarithm. Simplify the fraction by canceling (x - 3).✓ Proved
  5. \[ = \left(x - 3\right) \left(2 \ln{\left(x - 3 \right)} + 1\right) \]
    algebraFactor out the common term (x - 3).✓ Proved
Answer \( \left(x - 3\right) \left(2 \log{\left(x - 3 \right)} + 1\right) \)

✓ 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
6✓ 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
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-21
  • gpt-oss:20b: pass 2026-09-21
  • qwen3.6:27b-mlx: pass 2026-09-21
  • gpt-oss:20b: pass 2026-09-21

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 2026-09-26 with SymPy 1.14.0.