∫Calc Practice

Derivative of \( \displaystyle \frac{\ln{\left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)} \right)}}{4} \)

Problem 2.1029 · hard

Differentiate \( \displaystyle f(x) = \frac{\ln{\left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)} \right)}}{4} \).
  1. \[ \frac{d}{d x} \frac{\ln{\left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)} \right)}}{4} \]
    Start with the derivative of the function.✓ Proved
  2. \[ = \frac{\frac{d}{d x} \ln{\left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)} \right)}}{4} \]
    constant-multiplePull out the constant factor.✓ Proved
  3. \[ = \frac{\frac{d}{d x} \left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}\right)}{4 \left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}\right)} \]
    chainApply the chain rule for the logarithm.✓ Proved
  4. \[ = \frac{\frac{d}{d x} \cot{\left(4 x + 1 \right)} + \frac{d}{d x} \csc{\left(4 x + 1 \right)}}{4 \left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}\right)} \]
    sumDifferentiate the sum inside the parentheses.✓ Proved
  5. \[ = \frac{- \cot{\left(4 x + 1 \right)} \csc{\left(4 x + 1 \right)} \frac{d}{d x} \left(4 x + 1\right) - \csc^{2}{\left(4 x + 1 \right)} \frac{d}{d x} \left(4 x + 1\right)}{4 \left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}\right)} \]
    trigApply the derivatives of cot and csc.✓ Proved
  6. \[ = \frac{- 4 \cot{\left(4 x + 1 \right)} \csc{\left(4 x + 1 \right)} - 4 \csc^{2}{\left(4 x + 1 \right)}}{4 \left(\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}\right)} \]
    chainDifferentiate the inner linear function 4x + 1.✓ Proved
  7. \[ = \frac{- \cot{\left(4 x + 1 \right)} \csc{\left(4 x + 1 \right)} - \csc^{2}{\left(4 x + 1 \right)}}{\cot{\left(4 x + 1 \right)} + \csc{\left(4 x + 1 \right)}} \]
    constant-multiple simplifyFactor out the 4. Cancel the 4 and the 1/4.✓ Proved
  8. \[ = - \csc{\left(4 x + 1 \right)} \]
    algebra simplifyFactor out -csc(4*x + 1) from the numerator. Simplify the fraction.✓ Proved
Answer \( - \frac{1}{\sin{\left(4 x + 1 \right)}} \)
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 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
csc has poles at multiples of pi
cot has poles at multiples of pi
3✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
log is undefined for non-positive arguments
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
4✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
5✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
6✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
7✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
8✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
9✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
cot has poles at multiples of pi
undefined where cot(4*x + 1) + csc(4*x + 1) = 0
10✓ Provedsympy 1.14.0simplify(a - b) reduced to 0
csc has poles at multiples of pi
answer✓ Provedsympy 1.14.0final line against the stated answer: simplify(a - b) reduced to 0
undefined where sin(4*x + 1) = 0
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
Every verdict on record (4)
  • qwen3.6:27b-mlx: pass 2026-09-27
  • gpt-oss:20b: pass 2026-09-27
  • qwen3.6:27b-mlx: pass 2026-09-27
  • gpt-oss:20b: pass 2026-09-27

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 2026-09-27 with SymPy 1.14.0.