∫Calc Practice

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

Problem 2.461 · medium

Differentiate \( \displaystyle f(x) = \left(x - 2\right)^{x - 3} \).
  1. \[ \frac{d}{d x} \left(x - 2\right)^{x - 3} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} e^{\left(x - 3\right) \ln{\left(x - 2 \right)}} \]
    rewriteRewrite the base and exponent using the exponential and logarithm.≈ Checked numerically
  3. \[ = e^{\left(x - 3\right) \ln{\left(x - 2 \right)}} \frac{d}{d x} \left(x - 3\right) \ln{\left(x - 2 \right)} \]
    chainApply the chain rule.✓ Proved
  4. \[ = \left(\left(x - 3\right) \frac{d}{d x} \ln{\left(x - 2 \right)} + \ln{\left(x - 2 \right)} \frac{d}{d x} \left(x - 3\right)\right) e^{\left(x - 3\right) \ln{\left(x - 2 \right)}} \]
    productApply the product rule to the inner expression.✓ Proved
  5. \[ = \left(\left(x - 3\right) \frac{d}{d x} \ln{\left(x - 2 \right)} + \ln{\left(x - 2 \right)}\right) e^{\left(x - 3\right) \ln{\left(x - 2 \right)}} \]
    derivativeDifferentiate the first part of the product.✓ Proved
  6. \[ = \left(\frac{x - 3}{x - 2} + \ln{\left(x - 2 \right)}\right) e^{\left(x - 3\right) \ln{\left(x - 2 \right)}} \]
    derivativeDifferentiate the second part of the product.✓ Proved
  7. \[ = \left(x - 2\right)^{x - 3} \left(\frac{x - 3}{x - 2} + \ln{\left(x - 2 \right)}\right) \]
    simplifyConvert the exponential back to its original form.≈ Checked numerically
  8. \[ = \left(x - 2\right)^{x - 3} \left(\ln{\left(x - 2 \right)} + 1 - \frac{1}{x - 2}\right) \]
    algebraSplit the fraction inside the parentheses.✓ Proved
  9. \[ = \left(x - 2\right)^{x - 3} \left(\frac{x - 3}{x - 2} + \ln{\left(x - 2 \right)}\right) \]
    simplifyKeep the fraction form for the final answer.✓ Proved
Answer \( \left(x - 2\right)^{x - 3} \left(\frac{x - 3}{x - 2} + \log{\left(x - 2 \right)}\right) \)

✓ Nihil obstat Lines: 8 proved, 2 checked numerically. 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≈ Checked numericallysympy 1.14.0sympy 1.14.0: simplify left ((x - 2)**(x - 3)*(x + (x - 2)*log(x - 2) - 3) + (-x - (x - 2)*log(x - 2) + 3)*exp((x - 3)*log(x - 2)))/(x - 2); numeric agreement only, at 24 of 24 sampled points
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
undefined where x - 2 = 0
7≈ Checked numericallysympy 1.14.0sympy 1.14.0: simplify left ((x - 2)**(x - 3)*(-x - (x - 2)*log(x - 2) + 3) + (x + (x - 2)*log(x - 2) - 3)*exp((x - 3)*log(x - 2)))/(x - 2); numeric agreement only, at 24 of 24 sampled points
log is undefined for non-positive arguments
undefined where x - 2 = 0
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where x - 2 = 0
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where x - 2 = 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
log is undefined for non-positive arguments
undefined where x - 2 = 0
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 (6)
  • qwen3.6:27b-mlx: pass 2026-09-21
  • gpt-oss:20b: pass 2026-09-21
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies logarithmic differentiation, adhering to the one-rule-per-step constraint and using valid labels from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies logarithmic differentiation, adhering to the one-rule-per-step constraint and using valid labels from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-09-20

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.