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Derivative of \( \displaystyle 2 x \left(25 x^{2} + 15 x + 3\right) \)

Problem 2.1087 · hard

Differentiate \( \displaystyle f(x) = 2 x \left(25 x^{2} + 15 x + 3\right) \).
  1. \[ \frac{d}{d x} 2 x \left(25 x^{2} + 15 x + 3\right) \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = 2 x \frac{d}{d x} \left(25 x^{2} + 15 x + 3\right) + \left(25 x^{2} + 15 x + 3\right) \frac{d}{d x} 2 x \]
    productApply the product rule.✓ Proved
  3. \[ = 50 x^{2} + 2 x \frac{d}{d x} \left(25 x^{2} + 15 x + 3\right) + 30 x + 6 \]
    constant-multipleFactor out the constant 2 from the first term.✓ Proved
  4. \[ = 50 x^{2} + 2 x \left(\frac{d}{d x} 3 + \frac{d}{d x} 15 x + \frac{d}{d x} 25 x^{2}\right) + 30 x + 6 \]
    sumApply the sum rule to the second term.✓ Proved
  5. \[ = 50 x^{2} + 2 x \left(50 x + 15\right) + 30 x + 6 \]
    derivative simplifyDifferentiate each term inside the parentheses. Simplify the expression by removing the zero.✓ Proved
  6. \[ = 150 x^{2} + 60 x + 6 \]
    algebra simplifyDistribute the terms. Combine like terms.✓ Proved
Answer \( 6 \left(5 x + 1\right)^{2} \)

✓ 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
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
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
8✓ 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 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint and using valid labels from the fixed vocabulary.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-28 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint and using valid labels from the fixed vocabulary.
  • gpt-oss:20b: pass 2026-09-28
  • qwen3.6:27b-mlx: pass 2026-09-28
  • gpt-oss:20b: fail (style) 2026-09-28 — Step 7 distributes both products in one line, applying two algebraic expansions at once, violating the rule that each step must change only one thing.

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 2026-09-28 with SymPy 1.14.0.