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Derivative of \( \displaystyle \frac{3 x}{2} - \frac{3 \sin{\left(10 x + 2 \right)}}{20} \)

Problem 2.1107 · hard

Differentiate \( \displaystyle f(x) = \frac{3 x}{2} - \frac{3 \sin{\left(10 x + 2 \right)}}{20} \).
  1. \[ \frac{d}{d x} \left(\frac{3 x}{2} - \frac{3 \sin{\left(10 x + 2 \right)}}{20}\right) \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} \frac{3 x}{2} - \frac{d}{d x} \frac{3 \sin{\left(10 x + 2 \right)}}{20} \]
    sum constant-multipleApply the difference rule. Factor out the constants.✓ Proved
  3. \[ = \frac{3 \frac{d}{d x} x}{2} - \frac{3 \frac{d}{d x} \sin{\left(10 x + 2 \right)}}{20} \]
    constant-multipleFactor out the constants from each term.✓ Proved
  4. \[ = \frac{3}{2} - \frac{3 \frac{d}{d x} \sin{\left(10 x + 2 \right)}}{20} \]
    derivative simplifyDifferentiate the first term. Simplify the first term.✓ Proved
  5. \[ = - \frac{3 \cos{\left(10 x + 2 \right)} \frac{d}{d x} \left(10 x + 2\right)}{20} + \frac{3}{2} \]
    chainApply the chain rule to the sine function.✓ Proved
  6. \[ = - \frac{3 \cos{\left(10 x + 2 \right)} \frac{d}{d x} x}{2} + \frac{3}{2} \]
    derivativeDifferentiate the inner function.✓ Proved
  7. \[ = \frac{3}{2} - \frac{3 \cos{\left(10 x + 2 \right)}}{2} \]
    derivative simplify algebraDifferentiate the variable x. Simplify the derivative of x. Multiply 3/20 by 10.✓ Proved
  8. \[ = \frac{3}{2} - 1.5 \cos{\left(10 x + 2 \right)} \]
    simplifyConvert the fraction to a decimal.✓ Proved
Answer \( \frac{3}{2} - \frac{3 \cos{\left(10 x + 2 \right)}}{2} \)

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. The reviewers disagree about how one step is explained; every verdict is in the receipt.

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
12✓ 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. All labels are valid and accurately describe the transformations performed.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-28 — The solution correctly applies differentiation rules step-by-step, adhering to the one-change-per-step constraint. All labels are valid and accurately describe the transformations performed.
  • gpt-oss:20b: pass 2026-09-28
  • qwen3.6:27b-mlx: pass 2026-09-28 — 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: fail (error) 2026-09-28 — Step 8 applies two rules at once (constant‑multiple and derivative) and labels the operation as "derivative" instead of the appropriate "constant‑multiple" rule. This violates the one‑rule‑per‑step requirement.

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.