Derivative of \( \displaystyle \sqrt{1 - \left(4 x + 2\right)^{2}} + \left(4 x + 2\right) \operatorname{asin}{\left(4 x + 2 \right)} \)
Problem 2.633 · hard
Differentiate \( \displaystyle f(x) = \sqrt{1 - \left(4 x + 2\right)^{2}} + \left(4 x + 2\right) \operatorname{asin}{\left(4 x + 2 \right)} \).
- \[ \frac{d}{d x} \left(\sqrt{1 - \left(4 x + 2\right)^{2}} + \left(4 x + 2\right) \operatorname{asin}{\left(4 x + 2 \right)}\right) \]sumStart with the derivative of the entire function.✓ Proved
- \[ = \frac{d}{d x} \left(4 x + 2\right) \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} \]sumSplit the derivative into two parts.✓ Proved
- \[ = \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{d}{d x} \left(4 x \operatorname{asin}{\left(4 x + 2 \right)} + 2 \operatorname{asin}{\left(4 x + 2 \right)}\right) \]algebraExpand the second term.✓ Proved
- \[ = \frac{d}{d x} 4 x \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{d}{d x} 2 \operatorname{asin}{\left(4 x + 2 \right)} \]sumSplit the derivative of the expanded term.✓ Proved
- \[ = 4 x \frac{d}{d x} \operatorname{asin}{\left(4 x + 2 \right)} + \operatorname{asin}{\left(4 x + 2 \right)} \frac{d}{d x} 4 x + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{d}{d x} 2 \operatorname{asin}{\left(4 x + 2 \right)} \]productApply the product rule to the second term.✓ Proved
- \[ = 4 x \frac{d}{d x} \operatorname{asin}{\left(4 x + 2 \right)} + 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{d}{d x} 2 \operatorname{asin}{\left(4 x + 2 \right)} \]derivativeDifferentiate 4*x.✓ Proved
- \[ = 4 x \frac{d}{d x} \operatorname{asin}{\left(4 x + 2 \right)} + 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + 2 \frac{d}{d x} \operatorname{asin}{\left(4 x + 2 \right)} \]constant-multipleDifferentiate 2*asin(4*x + 2) by pulling out the constant.✓ Proved
- \[ = \left(4 x + 2\right) \frac{d}{d x} \operatorname{asin}{\left(4 x + 2 \right)} + 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} \]algebraCombine the terms involving the derivative of asin.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{\left(4 x + 2\right) \frac{d}{d x} \left(4 x + 2\right)}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]inverse-trigApply the derivative rule for arcsine.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{4 \left(4 x + 2\right)}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]derivativeDifferentiate 4*x + 2.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{d}{d x} \sqrt{1 - \left(4 x + 2\right)^{2}} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]algebra rewriteMultiply the terms in the last part. Rewrite the square root as a power.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} + \frac{\frac{d}{d x} \left(1 - \left(4 x + 2\right)^{2}\right)}{2 \sqrt{1 - \left(4 x + 2\right)^{2}}} \]chainApply the chain rule to the power term.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} + \frac{\frac{d}{d x} 1 - \frac{d}{d x} \left(4 x + 2\right)^{2}}{2 \sqrt{1 - \left(4 x + 2\right)^{2}}} \]sumSplit the derivative inside the power term.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} - \frac{\frac{d}{d x} \left(4 x + 2\right)^{2}}{2 \sqrt{1 - \left(4 x + 2\right)^{2}}} \]derivative constant-multipleDifferentiate the constant 1. Handle the negative sign.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} - \frac{\left(8 x + 4\right) \frac{d}{d x} \left(4 x + 2\right)}{2 \sqrt{1 - \left(4 x + 2\right)^{2}}} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]powerApply the power rule to (4*x + 2)**2.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{- 32 x - 16}{2 \sqrt{1 - \left(4 x + 2\right)^{2}}} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]derivative algebraDifferentiate 4*x + 2. Multiply the terms.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} + \frac{- 16 x - 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} + \frac{16 x + 8}{\sqrt{1 - \left(4 x + 2\right)^{2}}} \]algebraSimplify the first term.✓ Proved
- \[ = 4 \operatorname{asin}{\left(4 x + 2 \right)} \]algebra algebra algebra simplifyCombine the fractions with the same denominator. Expand the numerator. Simplify the numerator. Final simplification.✓ Proved
Answer \( 4 \operatorname{asin}{\left(4 x + 2 \right)} \)
✓ 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
| 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 asin is real only on [-1, 1] |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 11 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 12 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 13 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 14 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 15 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 16 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 17 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 18 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 19 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 20 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 21 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] undefined where 1 - (4*x + 2)**2 = 0 |
| 22 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 23 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 24 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 asin is real only on [-1, 1] |
| 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 — The solution correctly applies differentiation rules step-by-step, adhering to the single-change constraint and using valid labels from the fixed vocabulary. The algebraic simplifications are correct and lead to the stated answer.
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-09-21 — The solution correctly applies differentiation rules step-by-step, adhering to the single-change constraint and using valid labels from the fixed vocabulary. The algebraic simplifications are correct and lead to the stated answer.gpt-oss:20b: pass 2026-09-21qwen3.6:27b-mlx: pass 2026-09-21 — The solution correctly applies differentiation rules step-by-step, adhering to the single-rule-per-step constraint. The algebraic simplifications and rule labels are accurate.gpt-oss:20b: pass 2026-09-21
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.