Derivative of \( \displaystyle 5 x e^{x} - 5 e^{x} \)
Problem 2.1839 · hard Beautiful
Differentiate \( \displaystyle f(x) = 5 x e^{x} - 5 e^{x} \).
- \[ \frac{d}{d x} \left(5 x e^{x} - 5 e^{x}\right) \]sumStart with the derivative of the entire expression.✓ Proved
- \[ = \frac{d}{d x} 5 x e^{x} - \frac{d}{d x} 5 e^{x} \]sumApply the sum rule to differentiate each term separately.✓ Proved
- \[ = 5 \frac{d}{d x} x e^{x} - 5 \frac{d}{d x} e^{x} \]constant-multiple algebraFactor out the constant 5 from both terms. Factor out the constant 5.✓ Proved
- \[ = 5 x \frac{d}{d x} e^{x} + 5 e^{x} \frac{d}{d x} x - 5 \frac{d}{d x} e^{x} \]productApply the product rule to the first term.✓ Proved
- \[ = 5 x \frac{d}{d x} e^{x} + 5 e^{x} - 5 \frac{d}{d x} e^{x} \]derivative algebraDifferentiate x with respect to x. Distribute the derivative operator.✓ Proved
- \[ = 5 \left(x - 1\right) \frac{d}{d x} e^{x} + 5 e^{x} \]algebraFactor out the common derivative term.✓ Proved
- \[ = 5 \left(x - 1\right) e^{x} + 5 e^{x} \]exponentialDifferentiate the exponential function exp(x).✓ Proved
- \[ = 5 x e^{x} \]algebra simplifyDistribute the term (x - 1). Combine like terms to get the final result.✓ Proved
Answer \( 5 x e^{x} \)
✓ 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 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 11 | ✓ 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)
qwen3.6:27b-mlx: pass 2026-10-08gpt-oss:20b: pass 2026-10-08gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: pass 2026-10-08
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 2026-10-08 with SymPy 1.14.0.