Derivative of \( \displaystyle - x e^{3 x} + \frac{e^{3 x}}{3} \)
Problem 2.1781 · hard
Differentiate \( \displaystyle f(x) = - x e^{3 x} + \frac{e^{3 x}}{3} \).
- \[ \frac{d}{d x} \left(- x e^{3 x} + \frac{e^{3 x}}{3}\right) \]sumStart with the derivative of the entire expression.✓ Proved
- \[ = \frac{d}{d x} \left(- x e^{3 x}\right) + \frac{d}{d x} \frac{e^{3 x}}{3} \]sum constant-multipleSplit the derivative into two parts using the sum rule. Pull out the constant 1/3 from the second term.✓ Proved
- \[ = \frac{d}{d x} \left(- x e^{3 x}\right) + \frac{\frac{d}{d x} e^{3 x}}{3} \]constant-multiplePull out the constant -1 from the first term.✓ Proved
- \[ = - x \frac{d}{d x} e^{3 x} - e^{3 x} \frac{d}{d x} x + \frac{\frac{d}{d x} e^{3 x}}{3} \]productApply the product rule to the first term.✓ Proved
- \[ = - x \frac{d}{d x} e^{3 x} - e^{3 x} + \frac{\frac{d}{d x} e^{3 x}}{3} \]derivativeDifferentiate x.✓ Proved
- \[ = - 3 x e^{3 x} \]chain algebra simplifyApply the chain rule to exp(3*x). Simplify the products and constants. Combine like terms.✓ Proved
Answer \( - 3 x e^{3 x} \)
✓ 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 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 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
Every verdict on record (4)
gpt-oss:20b: pass 2026-10-07qwen3.6:27b-mlx: pass 2026-10-07gpt-oss:20b: pass 2026-10-07qwen3.6:27b-mlx: pass 2026-10-07 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint and using valid labels from the fixed vocabulary.
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 2026-10-07 with SymPy 1.14.0.