Derivative of \( \displaystyle \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \)
Problem 2.1031 · hard Beautiful
Differentiate \( \displaystyle f(x) = \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \).
- \[ \frac{d}{d x} \ln{\left(\frac{e^{- 3 x}}{9 x^{2}} \right)} \]derivativeStart with the derivative of the function.✓ Proved
- \[ = \frac{d}{d x} \left(- 3 x - \ln{\left(9 x^{2} \right)}\right) \]algebra simplifyUse the property log(a/b) = log(a) - log(b). Simplify log(exp(-3*x)) to -3*x.✓ Proved
- \[ = \frac{d}{d x} \left(- 3 x - \ln{\left(x^{2} \right)} - \ln{\left(9 \right)}\right) \]algebraUse the property log(ab) = log(a) + log(b).✓ Proved
- \[ = \frac{d}{d x} \left(- 3 x - 2 \ln{\left(x \right)} - \ln{\left(9 \right)}\right) \]powerUse the property log(x**n) = n*log(x).✓ Proved
- \[ = \frac{d}{d x} \left(- 3 x\right) - \frac{d}{d x} \ln{\left(9 \right)} - \frac{d}{d x} 2 \ln{\left(x \right)} \]sumApply the derivative to each term separately.✓ Proved
- \[ = - \frac{d}{d x} 2 \ln{\left(x \right)} - 3 \]constantThe derivative of the constant log(9) is 0.✓ Proved
- \[ = - 2 \frac{d}{d x} \ln{\left(x \right)} - 3 \]constant-multiplePull the constant 2 out of the derivative.✓ Proved
- \[ = -3 - \frac{2}{x} \]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
| Line | Status | Checked by | Detail |
|---|---|---|---|
| 1 | ✓ Proved | sympy 1.14.0 | line 1 is the problem as stated |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where x = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where x = 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated f directly and got the stated answer |
Reviewers
gpt-oss:20b: passqwen3.6:27b-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 2026-09-27qwen3.6:27b-mlx: pass 2026-09-27gpt-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.