∫Calc Practice

Derivative of \( \displaystyle \frac{\ln{\left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)} \right)}}{2} \)

Problem 2.352 · hard

Differentiate \( \displaystyle f(x) = \frac{\ln{\left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)} \right)}}{2} \).
  1. \[ \frac{d}{d x} \frac{\ln{\left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)} \right)}}{2} \]
    derivativeStart with the derivative of the function.✓ Proved
  2. \[ = \frac{\frac{d}{d x} \ln{\left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)} \right)}}{2} \]
    constant-multiplePull out the constant factor.✓ Proved
  3. \[ = \frac{\frac{d}{d x} \left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}\right)}{2 \left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}\right)} \]
    chainApply the chain rule for the logarithm.✓ Proved
  4. \[ = \frac{\frac{d}{d x} \tan{\left(2 x - 3 \right)} + \frac{d}{d x} \sec{\left(2 x - 3 \right)}}{2 \left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}\right)} \]
    sumDifferentiate the sum inside the parentheses.✓ Proved
  5. \[ = \frac{\tan{\left(2 x - 3 \right)} \sec{\left(2 x - 3 \right)} \frac{d}{d x} \left(2 x - 3\right) + \sec^{2}{\left(2 x - 3 \right)} \frac{d}{d x} \left(2 x - 3\right)}{2 \left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}\right)} \]
    trigApply the derivative rules for tan and sec.≈ Checked numerically
  6. \[ = \frac{2 \tan{\left(2 x - 3 \right)} \sec{\left(2 x - 3 \right)} + 2 \sec^{2}{\left(2 x - 3 \right)}}{2 \left(\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}\right)} \]
    chainApply the chain rule to the inner linear function.✓ Proved
  7. \[ = \frac{\tan{\left(2 x - 3 \right)} \sec{\left(2 x - 3 \right)} + \sec^{2}{\left(2 x - 3 \right)}}{\tan{\left(2 x - 3 \right)} + \sec{\left(2 x - 3 \right)}} \]
    algebra simplifyFactor out the common constant 2. Cancel the 1/2 and the 2.✓ Proved
  8. \[ = \sec{\left(2 x - 3 \right)} \]
    algebra simplifyFactor out sec(2*x - 3) from the numerator. Cancel the common factor in the numerator and denominator.✓ Proved
Answer \( \frac{1}{\cos{\left(2 x - 3 \right)}} \)
Mind the domain. The answer is also defined at points where f(x) is not. Substituting there gives a number that is not a slope of f.

✓ Nihil obstat Lines: 10 proved, 1 checked numerically. 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
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
5≈ Checked numericallysympy 1.14.0sympy 1.14.0: simplify left (tan(2*x - 3)**2 - sec(2*x - 3)**2 + 1)/(tan(2*x - 3) + sec(2*x - 3)); numeric agreement only, at 24 of 24 sampled points
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
tan has poles at odd multiples of pi/2
sec has poles at odd multiples of pi/2
undefined where tan(2*x - 3) + sec(2*x - 3) = 0
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
sec has poles at odd multiples of pi/2
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
undefined where cos(2*x - 3) = 0
answer, a second way✓ Provedsympy 1.14.0SymPy differentiated f directly and got the stated answer

Reviewers

  • gpt-oss:20b: pass
  • deepseek-r1:70b: pass
  • qwen3.6:27b-mlx: pass — The solution correctly applies differentiation rules and algebraic simplifications in single-step increments. The labels accurately reflect the operations performed, such as using 'chain' for the logarithmic derivative and inner function differentiation, and 'algebra'/'simplify' for factoring and cancellation.
Every verdict on record (10)
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies differentiation rules and algebraic simplifications in single-step increments. The labels accurately reflect the operations performed, such as using 'chain' for the logarithmic derivative and inner function differentiation, and 'algebra'/'simplify' for factoring and cancellation.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-20 — The solution correctly applies differentiation rules and algebraic simplifications. Each step changes only one aspect of the expression, and the labels accurately describe the operations performed.
  • gpt-oss:20b: pass 2026-09-20
  • qwen3.6:27b-mlx: pass 2026-09-19
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19
  • qwen3.6:27b-mlx: pass 2026-09-19
  • deepseek-r1:70b: pass 2026-09-19
  • gpt-oss:20b: pass 2026-09-19

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.