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Derivative of \( \displaystyle \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \)

Problem 2.1031 · hard Beautiful

Differentiate \( \displaystyle f(x) = \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \).
  1. \[ \frac{d}{d x} \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} \left(- 3 x - \ln{\left(9 x^{2} \right)}\right) \]
    algebra simplifyUse the property log(a/b) = log(a) - log(b). Simplify log(exp(-3*x)) to -3*x.✓ Proved
  3. \[ = \frac{d}{d x} \left(- 3 x - \ln{\left(x^{2} \right)} - \ln{\left(9 \right)}\right) \]
    algebraUse the property log(ab) = log(a) + log(b).✓ Proved
  4. \[ = \frac{d}{d x} \left(- 3 x - 2 \ln{\left(x \right)} - \ln{\left(9 \right)}\right) \]
    powerUse the property log(x**n) = n*log(x).✓ Proved
  5. \[ = \frac{d}{d x} \left(- 3 x\right) - \frac{d}{d x} \ln{\left(9 \right)} - \frac{d}{d x} 2 \ln{\left(x \right)} \]
    sumApply the derivative to each term separately.✓ Proved
  6. \[ = - \frac{d}{d x} 2 \ln{\left(x \right)} - 3 \]
    constantThe derivative of the constant log(9) is 0.✓ Proved
  7. \[ = - 2 \frac{d}{d x} \ln{\left(x \right)} - 3 \]
    constant-multiplePull the constant 2 out of the derivative.✓ Proved
  8. \[ = -3 - \frac{2}{x} \]
    logarithmic simplifyThe derivative of log(x) is 1/x. Simplify the expression.✓ Proved
Answer \( -3 - \frac{2}{x} \)

✓ 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
undefined where x = 0
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
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
undefined where x = 0
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
undefined where x = 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
undefined where x = 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 — The solution correctly applies logarithmic properties to simplify the function before differentiating, adhering to the one-change-per-step constraint and using valid rule labels.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-27 — The solution correctly applies logarithmic properties to simplify the function before differentiating, adhering to the one-change-per-step constraint and using valid rule labels.
  • gpt-oss:20b: pass 2026-09-27
  • qwen3.6:27b-mlx: pass 2026-09-27
  • gpt-oss:20b: pass 2026-09-27

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 2026-09-27 with SymPy 1.14.0.