Derivative of \( \displaystyle 4 x \left(- x^{2} - 3 x - 3\right) \)
Problem 2.1236 · hard
Differentiate \( \displaystyle f(x) = 4 x \left(- x^{2} - 3 x - 3\right) \).
- \[ \frac{d}{d x} 4 x \left(- x^{2} - 3 x - 3\right) \]derivativeStart with the derivative of the function.✓ Proved
- \[ = 4 \frac{d}{d x} x \left(- x^{2} - 3 x - 3\right) \]constant-multiplePull out the constant factor 4.✓ Proved
- \[ = 4 x \frac{d}{d x} \left(- x^{2} - 3 x - 3\right) + 4 \left(- x^{2} - 3 x - 3\right) \frac{d}{d x} x \]productApply the product rule.✓ Proved
- \[ = - 4 x^{2} + 4 x \frac{d}{d x} \left(- x^{2} - 3 x - 3\right) - 12 x - 12 \]derivativeDifferentiate the first part of the product.✓ Proved
- \[ = - 4 x^{2} + 4 x \frac{d}{d x} \left(-3\right) + 4 x \frac{d}{d x} \left(- 3 x\right) + 4 x \frac{d}{d x} \left(- x^{2}\right) - 12 x - 12 \]sumDifferentiate the second part of the product using the sum rule.✓ Proved
- \[ = - 12 x^{2} - 24 x - 12 \]derivative algebra algebra simplifyDifferentiate each term in the sum. Simplify the expression inside the parentheses. Combine like terms. Distribute the 4 and finalize the result.✓ Proved
Answer \( - 12 \left(x + 1\right)^{2} \)
✓ 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. The labels accurately reflect the operations performed.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-09-29 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. The labels accurately reflect the operations performed.gpt-oss:20b: pass 2026-09-29qwen3.6:27b-mlx: pass 2026-09-29gpt-oss:20b: pass 2026-09-29
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 2026-09-29 with SymPy 1.14.0.