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Derivative of \( \displaystyle - \frac{x^{2}}{2} + \ln{\left(\left(2 x\right)^{x^{2}} \right)} \)

Problem 2.2057 · hard

Differentiate \( \displaystyle f(x) = - \frac{x^{2}}{2} + \ln{\left(\left(2 x\right)^{x^{2}} \right)} \).
  1. \[ \frac{d}{d x} \left(- \frac{x^{2}}{2} + \ln{\left(\left(2 x\right)^{x^{2}} \right)}\right) \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{d}{d x} \ln{\left(\left(2 x\right)^{x^{2}} \right)} \]
    sumApply the sum rule.✓ Proved
  3. \[ = \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{d}{d x} x^{2} \ln{\left(2 x \right)} \]
    rewriteRewrite the logarithm using the property log(a^b) = b*log(a).✓ Proved
  4. \[ = \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{d}{d x} x^{2} \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right) \]
    algebraExpand the logarithm of the product.✓ Proved
  5. \[ = \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \frac{d}{d x} x^{2} \ln{\left(2 \right)} + \frac{d}{d x} x^{2} \ln{\left(x \right)} \]
    sumApply the sum rule again.✓ Proved
  6. \[ = \frac{d}{d x} \left(- \frac{x^{2}}{2}\right) + \ln{\left(2 \right)} \frac{d}{d x} x^{2} + \frac{d}{d x} x^{2} \ln{\left(x \right)} \]
    constant-multiplePull out the constant log(2).✓ Proved
  7. \[ = - x + \ln{\left(2 \right)} \frac{d}{d x} x^{2} + \frac{d}{d x} x^{2} \ln{\left(x \right)} \]
    derivativeDifferentiate the first term.✓ Proved
  8. \[ = - x + 2 x \ln{\left(2 \right)} + \frac{d}{d x} x^{2} \ln{\left(x \right)} \]
    derivativeDifferentiate the second term.✓ Proved
  9. \[ = x^{2} \frac{d}{d x} \ln{\left(x \right)} - x + 2 x \ln{\left(2 \right)} + \ln{\left(x \right)} \frac{d}{d x} x^{2} \]
    productApply the product rule to the third term.✓ Proved
  10. \[ = 2 x \ln{\left(x \right)} + 2 x \ln{\left(2 \right)} \]
    derivative algebra algebra simplifyDifferentiate the components of the product rule. Simplify the term x**2/x. Distribute the terms. Combine like terms.✓ Proved
  11. \[ = 2 x \left(\ln{\left(x \right)} + \ln{\left(2 \right)}\right) \]
    simplifyFactor out 2*x.✓ Proved
  12. \[ = 2 x \ln{\left(2 x \right)} \]
    simplifyCombine the logarithms.✓ Proved
Answer \( 2 x \ln{\left(2 x \right)} \)

✓ 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
LineStatusChecked byDetail
1✓ Provedsympy 1.14.0line 1 is the problem as stated
2✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
11✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
12✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
13✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
14✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
15✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
log is undefined for non-positive arguments
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 and algebraic simplifications in a step-by-step manner. Each step adheres to the single-rule constraint and uses valid labels from the provided vocabulary.
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-10-11 — 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 provided vocabulary.
  • gpt-oss:20b: pass 2026-10-11
  • gpt-oss:20b: pass 2026-10-11
  • qwen3.6:27b-mlx: pass 2026-10-11 — The solution correctly applies differentiation rules and algebraic simplifications in single-step increments. The labels accurately reflect 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 2026-10-11 with SymPy 1.14.0.