Derivative of \( \displaystyle - \frac{\sqrt{2} e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)}}{2} \)
Problem 2.883 · hard
Differentiate \( \displaystyle f(x) = - \frac{\sqrt{2} e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)}}{2} \).
- \[ \frac{d}{d x} \left(- \frac{\sqrt{2} e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)}}{2}\right) \]Start with the derivative of the function.✓ Proved
- \[ = - \frac{\sqrt{2} \frac{d}{d x} e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)}}{2} \]constant-multiplePull out the constant factor.✓ Proved
- \[ = - \frac{\sqrt{2} \left(e^{x + 2} \frac{d}{d x} \cos{\left(x + \frac{\pi}{4} + 2 \right)} + \cos{\left(x + \frac{\pi}{4} + 2 \right)} \frac{d}{d x} e^{x + 2}\right)}{2} \]productApply the product rule.✓ Proved
- \[ = - \frac{\sqrt{2} \left(e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)} + e^{x + 2} \frac{d}{d x} \cos{\left(x + \frac{\pi}{4} + 2 \right)}\right)}{2} \]derivativeDifferentiate the first part of the product.✓ Proved
- \[ = - \frac{\sqrt{2} \left(- e^{x + 2} \sin{\left(x + \frac{\pi}{4} + 2 \right)} + e^{x + 2} \cos{\left(x + \frac{\pi}{4} + 2 \right)}\right)}{2} \]derivativeDifferentiate the second part of the product.✓ Proved
- \[ = - \frac{\sqrt{2} \left(- \sin{\left(x + \frac{\pi}{4} + 2 \right)} + \cos{\left(x + \frac{\pi}{4} + 2 \right)}\right) e^{x + 2}}{2} \]algebra rewrite simplifyFactor out the common term exp(x + 2). Use trigonometric identities if needed, but here we simplify the expression structure. The expression is already in its simplest form.✓ Proved
Answer \( e^{x + 2} \sin{\left(x + 2 \right)} \)
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 |
| 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: fail (error) — The solution fails to reach the stated answer. Step 7 and 8 are circular or incorrect manipulations that do not simplify the expression to exp(x+2)*sin(x+2). Specifically, the term in parentheses is cos(x+2+pi/4) - sin(x+2+pi/4), which simplifies to -sqrt(2)sin(x+2), but the steps shown do not perform this simplification correctly or at all, leaving the expression in a form that does not match the stated answer.
Every verdict on record (4)
qwen3.6:27b-mlx: fail (error) 2026-09-26 — The solution fails to reach the stated answer. Step 7 and 8 are circular or incorrect manipulations that do not simplify the expression to exp(x+2)*sin(x+2). Specifically, the term in parentheses is cos(x+2+pi/4) - sin(x+2+pi/4), which simplifies to -sqrt(2)sin(x+2), but the steps shown do not perform this simplification correctly or at all, leaving the expression in a form that does not match the stated answer.gpt-oss:20b: pass 2026-09-26qwen3.6:27b-mlx: fail (error) 2026-09-26 — The solution fails to reach the stated answer. Step 7 and 8 are circular and do not simplify the expression to exp(x+2)*sin(x+2). The intermediate result -sqrt(2)/2 * exp(x + 2) * (cos(x + pi/4 + 2) - sin(x + pi/4 + 2)) is not algebraically equivalent to the stated answer without further trigonometric simplification which is missing or incorrect.gpt-oss:20b: pass 2026-09-26
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.