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

Problem 2.1590 · hard

Differentiate \( \displaystyle f(x) = x e^{3 x} - \frac{e^{3 x}}{3} \).
  1. \[ \frac{d}{d x} \left(x e^{3 x} - \frac{e^{3 x}}{3}\right) \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} x e^{3 x} - \frac{d}{d x} \frac{e^{3 x}}{3} \]
    sum constantApply the sum rule. Factor out the constant 1/3.✓ Proved
  3. \[ = x \frac{d}{d x} e^{3 x} + e^{3 x} \frac{d}{d x} x - \frac{d}{d x} \frac{e^{3 x}}{3} \]
    productApply the product rule to the first term.✓ Proved
  4. \[ = x \frac{d}{d x} e^{3 x} + e^{3 x} - \frac{d}{d x} \frac{e^{3 x}}{3} \]
    derivativeDifferentiate x.✓ Proved
  5. \[ = x \frac{d}{d x} e^{3 x} + e^{3 x} - \frac{\frac{d}{d x} e^{3 x}}{3} \]
    constant-multipleFactor out 1/3 from the third term.✓ Proved
  6. \[ = \left(x - \frac{1}{3}\right) \frac{d}{d x} e^{3 x} + e^{3 x} \]
    algebraFactor out the common derivative term.✓ Proved
  7. \[ = \left(3 x - 1\right) e^{3 x} + e^{3 x} \]
    chain algebraDifferentiate exp(3*x) using the chain rule. Distribute the 3 into the parentheses.✓ Proved
  8. \[ = 3 x e^{3 x} \]
    algebra simplifyFactor out exp(3*x). Simplify the expression inside the parentheses.✓ Proved
Answer \( 3 x e^{3 x} \)

✓ 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
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
11✓ 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 2026-10-05
  • gpt-oss:20b: pass 2026-10-05
  • qwen3.6:27b-mlx: pass 2026-10-05 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. The labels used are appropriate for the operations performed.
  • gpt-oss:20b: pass 2026-10-05

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 2026-10-05 with SymPy 1.14.0.