Derivative of \( \displaystyle - 16 x^{3} - 24 x^{2} - 12 x \)
Problem 2.1507 · medium
Differentiate \( \displaystyle f(x) = - 16 x^{3} - 24 x^{2} - 12 x \).
- \[ \frac{d}{d x} \left(- 16 x^{3} - 24 x^{2} - 12 x\right) \]derivativeStart with the derivative of the function.✓ Proved
- \[ = \frac{d}{d x} \left(- 12 x\right) + \frac{d}{d x} \left(- 24 x^{2}\right) + \frac{d}{d x} \left(- 16 x^{3}\right) \]sumApply the sum rule.✓ Proved
- \[ = - 12 \frac{d}{d x} x - 24 \frac{d}{d x} x^{2} - 16 \frac{d}{d x} x^{3} \]constant-multipleFactor out the constants.✓ Proved
- \[ = - 48 x^{2} - 48 x - 12 \]power algebra simplifyApply the power rule to each term. Multiply the constants. Factor out the greatest common divisor.✓ Proved
Answer \( - 12 \left(2 x + 1\right)^{2} \)
✓ 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 |
| 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 the sum, constant-multiple, and power rules in separate steps, and the final simplification is algebraically valid.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-04 — The solution correctly applies the sum, constant-multiple, and power rules in separate steps, and the final simplification is algebraically valid.gpt-oss:20b: pass 2026-10-04qwen3.6:27b-mlx: pass 2026-10-04gpt-oss:20b: pass 2026-10-04
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 2026-10-04 with SymPy 1.14.0.