Derivative of \( \displaystyle \frac{\sqrt{25 x^{2} + 20 x + 5}}{5} \)
Problem 2.1918 · hard
Differentiate \( \displaystyle f(x) = \frac{\sqrt{25 x^{2} + 20 x + 5}}{5} \).
- \[ \frac{d}{d x} \frac{\sqrt{25 x^{2} + 20 x + 5}}{5} \]Start with the derivative of the function.✓ Proved
- \[ = \frac{\frac{d}{d x} \sqrt{25 x^{2} + 20 x + 5}}{5} \]constant-multiple rewritePull out the constant factor 1/5. Rewrite the square root as a fractional power.✓ Proved
- \[ = \frac{\frac{d}{d x} \left(25 x^{2} + 20 x + 5\right)}{10 \sqrt{25 x^{2} + 20 x + 5}} \]chain algebraApply the chain rule. Multiply the constants.✓ Proved
- \[ = \frac{\frac{d}{d x} 5 + \frac{d}{d x} 20 x + \frac{d}{d x} 25 x^{2}}{10 \sqrt{25 x^{2} + 20 x + 5}} \]sumDifferentiate the sum term by term.✓ Proved
- \[ = \frac{50 x + 20}{10 \sqrt{25 x^{2} + 20 x + 5}} \]derivative algebraDifferentiate each term in the sum. Simplify the derivative of the constant term.✓ Proved
- \[ = \frac{5 x + 2}{\sqrt{25 x^{2} + 20 x + 5}} \]rewriteMove the negative exponent to the denominator.✓ Proved
- \[ = \frac{50 x + 20}{10 \sqrt{25 x^{2} + 20 x + 5}} \]algebra algebraCombine the terms into a single fraction. Factor out 10 from the numerator.✓ Proved
- \[ = \frac{5 x + 2}{\sqrt{25 x^{2} + 20 x + 5}} \]simplifyCancel the common factor of 10.✓ Proved
Answer \( \frac{5 x + 2}{\sqrt{25 x^{2} + 20 x + 5}} \)
✓ 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 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 11 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| 12 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where 25*x**2 + 20*x + 5 = 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 — The solution correctly applies the constant multiple rule, chain rule, and sum rule in separate steps. All labels are valid and the algebraic simplifications are sound.
Every verdict on record (4)
gpt-oss:20b: pass 2026-10-09qwen3.6:27b-mlx: pass 2026-10-09 — The solution correctly applies the constant multiple rule, chain rule, and sum rule in separate steps. All labels are valid and the algebraic simplifications are sound.gpt-oss:20b: pass 2026-10-09qwen3.6:27b-mlx: pass 2026-10-09
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 2026-10-09 with SymPy 1.14.0.