Derivative of \( \displaystyle \operatorname{acos}{\left(5 x - 1 \right)} \)
Problem 2.459 · easy
Differentiate \( \displaystyle f(x) = \operatorname{acos}{\left(5 x - 1 \right)} \).
- \[ \frac{d}{d x} \operatorname{acos}{\left(5 x - 1 \right)} \]derivativeStart with the derivative of the function.✓ Proved
- \[ = - \frac{\frac{d}{d x} \left(5 x - 1\right)}{\sqrt{1 - \left(5 x - 1\right)^{2}}} \]inverse-trigApply the chain rule for the inverse cosine function.✓ Proved
- \[ = - \frac{5}{\sqrt{1 - \left(5 x - 1\right)^{2}}} \]derivative algebraDifferentiate the inner function 5*x - 1. Simplify the expression.✓ Proved
Answer \( - \frac{5}{\sqrt{1 - \left(5 x - 1\right)^{2}}} \)
✓ 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 acos is real only on [-1, 1] undefined where 1 - (5*x - 1)**2 = 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 1 - (5*x - 1)**2 = 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 1 - (5*x - 1)**2 = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where 1 - (5*x - 1)**2 = 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 2026-09-20gpt-oss:20b: pass 2026-09-20qwen3.6:27b-mlx: pass 2026-09-20gpt-oss:20b: pass 2026-09-20
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.