∫Calc Practice

Derivative of \( \displaystyle e^{- x} \sin{\left(x \right)} \)

Problem 2.369 · hard

Differentiate \( \displaystyle f(x) = e^{- x} \sin{\left(x \right)} \).
  1. \[ \frac{d}{d x} e^{- x} \sin{\left(x \right)} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = \sin{\left(x \right)} \frac{d}{d x} e^{- x} + e^{- x} \frac{d}{d x} \sin{\left(x \right)} \]
    productApply the product rule.✓ Proved
  3. \[ = - e^{- x} \sin{\left(x \right)} + e^{- x} \frac{d}{d x} \sin{\left(x \right)} \]
    chainDifferentiate the exponential part using the chain rule.✓ Proved
  4. \[ = - e^{- x} \sin{\left(x \right)} + e^{- x} \cos{\left(x \right)} \]
    derivativeDifferentiate the sine part.✓ Proved
  5. \[ = \left(- \sin{\left(x \right)} + \cos{\left(x \right)}\right) e^{- x} \]
    algebraFactor out the common term exp(-x).✓ Proved
Answer \( \left(- \sin{\left(x \right)} + \cos{\left(x \right)}\right) e^{- x} \)

✓ 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
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 (10)
  • 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 product rule, chain rule, and standard derivatives in separate steps. The final algebraic rearrangement is 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 — The solution correctly applies the product rule, chain rule, and standard derivatives in separate steps. The final algebraic simplification is valid.
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19

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.