Derivative of \( \displaystyle 5 x e^{4 x} - \frac{5 e^{4 x}}{4} \)
Problem 2.1574 · hard
Differentiate \( \displaystyle f(x) = 5 x e^{4 x} - \frac{5 e^{4 x}}{4} \).
- \[ \frac{d}{d x} \left(5 x e^{4 x} - \frac{5 e^{4 x}}{4}\right) \]Start with the derivative of the function.✓ Proved
- \[ = \frac{d}{d x} 5 x e^{4 x} - \frac{d}{d x} \frac{5 e^{4 x}}{4} \]sum constant-multipleApply the sum rule. Factor out the constant from the second term.✓ Proved
- \[ = 5 \frac{d}{d x} x e^{4 x} - \frac{5 \frac{d}{d x} e^{4 x}}{4} \]constant-multipleFactor out the constant from the first term.✓ Proved
- \[ = 5 x \frac{d}{d x} e^{4 x} + 5 e^{4 x} \frac{d}{d x} x - \frac{5 \frac{d}{d x} e^{4 x}}{4} \]productApply the product rule to the first term.✓ Proved
- \[ = 5 x \frac{d}{d x} e^{4 x} + 5 e^{4 x} - \frac{5 \frac{d}{d x} e^{4 x}}{4} \]derivativeDifferentiate x.✓ Proved
- \[ = 20 x e^{4 x} \]chain algebra simplifyDifferentiate exp(4*x) using the chain rule. Distribute and simplify the constants. Combine like terms.✓ Proved
Answer \( 20 x e^{4 x} \)
✓ 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 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. All labels are appropriate for the transformations performed.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. All labels are appropriate for the transformations performed.gpt-oss:20b: pass 2026-10-05qwen3.6:27b-mlx: pass 2026-10-05gpt-oss:20b: pass 2026-10-05
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 2026-10-05 with SymPy 1.14.0.