Derivative of \( \displaystyle \sqrt{2} \sqrt{x} \ln{\left(2 x \right)} \)
Problem 2.485 · hard
Differentiate \( \displaystyle f(x) = \sqrt{2} \sqrt{x} \ln{\left(2 x \right)} \).
- \[ \frac{d}{d x} \sqrt{2} \sqrt{x} \ln{\left(2 x \right)} \]derivativeStart with the derivative of the function.✓ Proved
- \[ = \sqrt{2} \frac{d}{d x} \sqrt{x} \ln{\left(2 x \right)} \]constant-multiplePull out the constant factor.✓ Proved
- \[ = \sqrt{2} \left(\sqrt{x} \frac{d}{d x} \ln{\left(2 x \right)} + \ln{\left(2 x \right)} \frac{d}{d x} \sqrt{x}\right) \]productApply the product rule.✓ Proved
- \[ = \sqrt{2} \left(\sqrt{x} \frac{d}{d x} \ln{\left(2 x \right)} + \ln{\left(2 x \right)} \frac{d}{d x} x^{0.5}\right) \]rewriteRewrite sqrt(x) as a power.✓ Proved
- \[ = \sqrt{2} \left(\frac{0.5 \ln{\left(2 x \right)}}{x^{0.5}} + \sqrt{x} \frac{d}{d x} \ln{\left(2 x \right)}\right) \]derivativeDifferentiate the power term.✓ Proved
- \[ = \sqrt{2} \left(\frac{0.5 \ln{\left(2 x \right)}}{x^{0.5}} + \frac{\frac{d}{d x} 2 x}{2 \sqrt{x}}\right) \]chainApply the chain rule to the logarithm.✓ Proved
- \[ = \sqrt{2} \left(\frac{0.5 \ln{\left(2 x \right)}}{x^{0.5}} + \frac{1}{\sqrt{x}}\right) \]derivative algebraDifferentiate the inner function 2x. Simplify the fraction.✓ Proved
- \[ = \sqrt{2} \left(\frac{0.5 \ln{\left(2 x \right)}}{x^{0.5}} + x^{-0.5}\right) \]algebraSimplify sqrt(x)/x to x**-0.5.✓ Proved
- \[ = \frac{\sqrt{2} \left(0.5 \ln{\left(2 x \right)} + 1\right)}{x^{0.5}} \]algebraFactor out x**-0.5.✓ Proved
- \[ = \sqrt{2} \left(\frac{0.5 \ln{\left(2 x \right)}}{x^{0.5}} + x^{-0.5}\right) \]simplifyFinal simplified form.✓ Proved
Answer \( \frac{\sqrt{2} \left(\log{\left(2 x \right)} + 2\right)}{2 \sqrt{x}} \)
✓ 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
| 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 log is undefined for non-positive arguments |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| 11 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 log is undefined for non-positive arguments undefined where x = 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 (6)
qwen3.6:27b-mlx: pass 2026-09-21gpt-oss:20b: pass 2026-09-21qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies differentiation rules and algebraic simplifications. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.gpt-oss:20b: pass 2026-09-20qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies differentiation rules and algebraic simplifications in a step-by-step manner. Each step adheres to the single-rule constraint and uses valid labels from the fixed vocabulary.gpt-oss:20b: fail (style) 2026-09-20 — Step 11 repeats the previous expression without any change, yet is labeled "simplify". This is a no‑op step that applies no rule and should be omitted or corrected.
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.