Derivative of \( \displaystyle \frac{3 e^{4 x} \sin{\left(4 x \right)}}{8} - \frac{3 e^{4 x} \cos{\left(4 x \right)}}{8} \)
Problem 2.1856 · hard
Differentiate \( \displaystyle f(x) = \frac{3 e^{4 x} \sin{\left(4 x \right)}}{8} - \frac{3 e^{4 x} \cos{\left(4 x \right)}}{8} \).
- \[ \frac{d}{d x} \left(\frac{3 e^{4 x} \sin{\left(4 x \right)}}{8} - \frac{3 e^{4 x} \cos{\left(4 x \right)}}{8}\right) \]derivative constant-multipleStart with the derivative of the function. Factor out the constant 3/8 from both terms.✓ Proved
- \[ = \frac{3 \frac{d}{d x} e^{4 x} \sin{\left(4 x \right)}}{8} - \frac{3 \frac{d}{d x} e^{4 x} \cos{\left(4 x \right)}}{8} \]sumApply the sum rule for derivatives.✓ Proved
- \[ = - \frac{3 e^{4 x} \frac{d}{d x} \cos{\left(4 x \right)}}{8} - \frac{3 \cos{\left(4 x \right)} \frac{d}{d x} e^{4 x}}{8} + \frac{3 \frac{d}{d x} e^{4 x} \sin{\left(4 x \right)}}{8} \]productApply the product rule to the second term.✓ Proved
- \[ = \frac{3 e^{4 x} \frac{d}{d x} \sin{\left(4 x \right)}}{8} - \frac{3 e^{4 x} \frac{d}{d x} \cos{\left(4 x \right)}}{8} + \frac{3 \sin{\left(4 x \right)} \frac{d}{d x} e^{4 x}}{8} - \frac{3 \cos{\left(4 x \right)} \frac{d}{d x} e^{4 x}}{8} \]productApply the product rule to the first term.✓ Proved
- \[ = 3 e^{4 x} \sin{\left(4 x \right)} \]chain algebra algebra simplify simplifyDifferentiate the exponential and trigonometric functions using the chain rule. Distribute the negative sign. Simplify the double negative. Combine like terms. Final simplification.✓ Proved
Answer \( 3 e^{4 x} \sin{\left(4 x \right)} \)
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
| 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 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 10 | ✓ 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
Every verdict on record (4)
gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: pass 2026-10-08gpt-oss:20b: fail (error) 2026-10-08 — Step 6 applies several chain‑rule substitutions at once (exp(4x), sin(4x), and cos(4x)), violating the rule that each step must change only one thing.qwen3.6:27b-mlx: pass 2026-10-08 — 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.
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 2026-10-08 with SymPy 1.14.0.