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Derivative of \( \displaystyle \left(3 x - \frac{3}{4}\right) e^{4 x} \)

Problem 2.539 · medium

Differentiate \( \displaystyle f(x) = \left(3 x - \frac{3}{4}\right) e^{4 x} \).
  1. \[ \frac{d}{d x} \left(3 x - \frac{3}{4}\right) e^{4 x} \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} \left(3 x e^{4 x} - \frac{3 e^{4 x}}{4}\right) \]
    algebraDistribute the term.✓ Proved
  3. \[ = \frac{d}{d x} 3 x e^{4 x} - \frac{d}{d x} \frac{3 e^{4 x}}{4} \]
    sumApply the sum rule.✓ Proved
  4. \[ = 3 \frac{d}{d x} x e^{4 x} - \frac{3 \frac{d}{d x} e^{4 x}}{4} \]
    constant-multipleFactor out the constants.✓ Proved
  5. \[ = 3 x \frac{d}{d x} e^{4 x} + 3 e^{4 x} \frac{d}{d x} x - \frac{3 \frac{d}{d x} e^{4 x}}{4} \]
    productApply the product rule to the first term.✓ Proved
  6. \[ = 3 x \frac{d}{d x} e^{4 x} + 3 e^{4 x} - \frac{3 \frac{d}{d x} e^{4 x}}{4} \]
    derivativeDifferentiate x.✓ Proved
  7. \[ = 12 x e^{4 x} \]
    exponential algebra simplifyDifferentiate exp(4*x). Distribute and simplify the constant multiplication. Combine like terms.✓ Proved
Answer \( 12 x e^{4 x} \)

✓ 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
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
  • 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 2026-09-21 — 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 2026-09-21
  • qwen3.6:27b-mlx: pass 2026-09-21 — 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 2026-09-21

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.