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Derivative of \( \displaystyle 2 x \left(25 x^{2} + 30 x + 12\right) \)

Problem 2.646 · hard

Differentiate \( \displaystyle f(x) = 2 x \left(25 x^{2} + 30 x + 12\right) \).
  1. \[ \frac{d}{d x} 2 x \left(25 x^{2} + 30 x + 12\right) \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} \left(50 x^{3} + 60 x^{2} + 24 x\right) \]
    algebraDistribute the 2*x into the parentheses.✓ Proved
  3. \[ = \frac{d}{d x} 24 x + \frac{d}{d x} 60 x^{2} + \frac{d}{d x} 50 x^{3} \]
    sumApply the sum rule for derivatives.✓ Proved
  4. \[ = 24 \frac{d}{d x} x + 60 \frac{d}{d x} x^{2} + 50 \frac{d}{d x} x^{3} \]
    constant-multiplePull out the constant coefficients.✓ Proved
  5. \[ = 150 x^{2} + 120 x + 24 \]
    power simplifyApply the power rule to each term. Multiply the constants to get the final result.✓ Proved
Answer \( 6 \left(5 x + 2\right)^{2} \)

✓ 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
LineStatusChecked byDetail
1✓ Provedsympy 1.14.0line 1 is the problem as stated
2✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
answer, a second way✓ Provedsympy 1.14.0SymPy differentiated f directly and got the stated answer

Reviewers

  • gpt-oss:20b: pass
  • qwen3.6:27b-mlx: pass
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-21
  • gpt-oss:20b: pass 2026-09-21
  • qwen3.6:27b-mlx: pass 2026-09-21 — The solution correctly expands the polynomial, applies the sum and constant multiple rules, and uses the power rule to differentiate each term. All steps adhere to the single-change constraint and use valid labels.
  • gpt-oss:20b: fail (style) 2026-09-21 — [domain objection, downgraded to style] Step 1 uses an undefined label "unlabelled"; it should be labeled with an appropriate rule such as "derivative" or "algebra".

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 2026-09-26 with SymPy 1.14.0.