∫Calc Practice

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

Problem 2.347 · medium

Differentiate \( \displaystyle f(x) = 2 x e^{4 x} \).
  1. \[ \frac{d}{d x} 2 x e^{4 x} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = 2 \frac{d}{d x} x e^{4 x} \]
    constant-multiplePull out the constant factor 2.✓ Proved
  3. \[ = 2 x \frac{d}{d x} e^{4 x} + 2 e^{4 x} \frac{d}{d x} x \]
    productApply the product rule.✓ Proved
  4. \[ = 2 x \frac{d}{d x} e^{4 x} + 2 e^{4 x} \]
    derivative simplifyDifferentiate x. Simplify the expression.✓ Proved
  5. \[ = 8 x e^{4 x} + 2 e^{4 x} \]
    chain algebraApply the chain rule to exp(4*x). Rearrange the terms.✓ Proved
  6. \[ = 2 \left(4 x + 1\right) e^{4 x} \]
    simplifyFactor out the common term exp(4*x) and simplify.✓ Proved
Answer \( \left(8 x + 2\right) e^{4 x} \)

✓ 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
  • deepseek-r1:70b: pass
  • qwen3.6:27b-mlx: pass
Every verdict on record (13)
  • qwen3.6:27b-mlx: pass 2026-09-20
  • 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. The algebraic simplifications and rearrangements are valid and properly labeled.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-19 — The solution correctly applies the constant multiple, product, and chain rules in separate steps. The labels and notes are accurate and consistent with the provided vocabulary.
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19
  • qwen3.6:27b-mlx: pass 2026-09-19 — The solution correctly applies the constant multiple, product, and chain rules in separate steps. All labels are appropriate and the algebraic simplifications are sound.
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19
  • qwen3.6:27b-mlx: pass 2026-09-18
  • deepseek-r1:70b: pass 2026-09-18
  • gpt-oss:20b: pass 2026-09-18

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.