Derivative of \( \displaystyle \frac{\sin{\left(3 x - 3 \right)}}{3} \)
Problem 2.405 · easy
Differentiate \( \displaystyle f(x) = \frac{\sin{\left(3 x - 3 \right)}}{3} \).
- \[ \frac{d}{d x} \frac{\sin{\left(3 x - 3 \right)}}{3} \]Start with the derivative of the function.✓ Proved
- \[ = \frac{\frac{d}{d x} \sin{\left(3 x - 3 \right)}}{3} \]constant-multiplePull out the constant factor 1/3.✓ Proved
- \[ = \frac{\cos{\left(3 x - 3 \right)} \frac{d}{d x} \left(3 x - 3\right)}{3} \]chainApply the chain rule.✓ Proved
- \[ = \cos{\left(3 x - 3 \right)} \]derivative simplifyDifferentiate the inner function 3*x - 3. Simplify the expression by canceling the 3s.✓ Proved
Answer \( \cos{\left(3 x - 3 \right)} \)
✓ 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
| Line | Status | Checked by | Detail |
|---|---|---|---|
| 1 | ✓ Proved | sympy 1.14.0 | line 1 is the problem as stated |
| 2 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated f directly and got the stated answer |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly applies the constant multiple rule, chain rule, and basic derivative rules in separate steps. The labels are accurate and the logic is sound.
Every verdict on record (6)
qwen3.6:27b-mlx: pass 2026-09-21 — The solution correctly applies the constant multiple rule, chain rule, and basic derivative rules in separate steps. The labels are accurate and the logic is sound.gpt-oss:20b: pass 2026-09-21qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies the constant multiple rule, chain rule, and derivative of the inner function in separate steps. The final simplification is algebraically sound.gpt-oss:20b: fail (style) 2026-09-20 — Step 1 uses an unlabelled rule; it should be labeled "derivative". The rest of the steps are fine.qwen3.6:27b-mlx: pass 2026-09-20gpt-oss:20b: pass 2026-09-20
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.