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Derivative of \( \displaystyle - \frac{\sqrt{2} e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}}{6} \)

Problem 2.1136 · hard

Differentiate \( \displaystyle f(x) = - \frac{\sqrt{2} e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}}{6} \).
  1. \[ \frac{d}{d x} \left(- \frac{\sqrt{2} e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}}{6}\right) \]
    Start with the derivative of the function.✓ Proved
  2. \[ = - \frac{\sqrt{2} \frac{d}{d x} e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}}{6} \]
    constant-multiplePull out the constant factor.✓ Proved
  3. \[ = - \frac{\sqrt{2} \left(e^{3 x + 2} \frac{d}{d x} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)} + \cos{\left(3 x + \frac{\pi}{4} + 2 \right)} \frac{d}{d x} e^{3 x + 2}\right)}{6} \]
    productApply the product rule.✓ Proved
  4. \[ = - \frac{\sqrt{2} \left(- 3 e^{3 x + 2} \sin{\left(3 x + \frac{\pi}{4} + 2 \right)} + 3 e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}\right)}{6} \]
    chain algebraApply the chain rule to both terms. Simplify the terms inside the parentheses.✓ Proved
  5. \[ = - \frac{\sqrt{2} \left(- e^{3 x + 2} \sin{\left(3 x + \frac{\pi}{4} + 2 \right)} + e^{3 x + 2} \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}\right)}{2} \]
    constant-multiple simplifyFactor out the common constant 3. Simplify the fraction 3/6 to 1/2.✓ Proved
  6. \[ = - \frac{\sqrt{2} \left(- \sin{\left(3 x + \frac{\pi}{4} + 2 \right)} + \cos{\left(3 x + \frac{\pi}{4} + 2 \right)}\right) e^{3 x + 2}}{2} \]
    algebraFactor out the exponential term.✓ Proved
Answer \( e^{3 x + 2} \sin{\left(3 x + 2 \right)} \)

✓ 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
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-28
  • gpt-oss:20b: pass 2026-09-28
  • qwen3.6:27b-mlx: pass 2026-09-28 — The solution correctly applies differentiation rules and algebraic simplifications. The final expression is mathematically equivalent to the stated answer via trigonometric identities, and no steps violate the one-rule-per-step constraint.
  • gpt-oss:20b: pass 2026-09-28

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.