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Derivative of \( \displaystyle 2 x e^{4 x + 1} \)

Problem 2.292 · hard

Differentiate \( \displaystyle f(x) = 2 x e^{4 x + 1} \).
  1. \[ \frac{d}{d x} 2 x e^{4 x + 1} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = 2 \frac{d}{d x} x e^{4 x + 1} \]
    constant-multiplePull out the constant factor 2.✓ Proved
  3. \[ = 2 x \frac{d}{d x} e^{4 x + 1} + 2 e^{4 x + 1} \frac{d}{d x} x \]
    productApply the product rule to the remaining terms.✓ Proved
  4. \[ = 2 x \frac{d}{d x} e^{4 x + 1} + 2 e^{4 x + 1} \]
    derivativeDifferentiate the first part of the product.✓ Proved
  5. \[ = 2 x e^{4 x + 1} \frac{d}{d x} \left(4 x + 1\right) + 2 e^{4 x + 1} \]
    chainApply the chain rule to the exponential term.✓ Proved
  6. \[ = 8 x e^{4 x + 1} + 2 e^{4 x + 1} \]
    derivative algebraDifferentiate the inner function 4*x + 1. Simplify the expression inside the parentheses.✓ Proved
  7. \[ = 2 \left(4 x + 1\right) e^{4 x + 1} \]
    algebraFactor out the common exponential term.✓ Proved
  8. \[ = \left(8 x + 2\right) e^{4 x + 1} \]
    simplifyFinal simplified form.✓ Proved
Answer \( \left(8 x + 2\right) e^{4 x + 1} \)

✓ 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
9✓ 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
  • deepseek-r1:70b: pass
  • qwen3.6:27b-mlx: pass — The solution correctly applies the constant multiple, product, and chain rules in separate steps. The labels accurately reflect the operations performed, and the algebraic simplifications are valid.
Every verdict on record (12)
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies the constant multiple, product, and chain rules in separate steps. The labels accurately reflect the operations performed, and the algebraic simplifications are valid.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies the constant multiple, product, and chain rules in separate steps. All labels correspond to the operations performed, and the algebraic simplifications are valid.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-19
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19
  • qwen3.6:27b-mlx: pass 2026-09-19
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-17
  • deepseek-r1:70b: pass 2026-09-17

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.