Derivative of \( \displaystyle \frac{3 \sqrt{4 x^{2} + 8 x + 5}}{2} \)
Problem 2.1565 · hard
Differentiate \( \displaystyle f(x) = \frac{3 \sqrt{4 x^{2} + 8 x + 5}}{2} \).
- \[ \frac{d}{d x} \frac{3 \sqrt{4 x^{2} + 8 x + 5}}{2} \]Start with the derivative of the function.✓ Proved
- \[ = \frac{3 \frac{d}{d x} \sqrt{4 x^{2} + 8 x + 5}}{2} \]constant-multiple rewritePull out the constant factor. Rewrite the square root as a fractional power.✓ Proved
- \[ = \frac{3 \frac{d}{d x} \left(4 x^{2} + 8 x + 5\right)}{4 \sqrt{4 x^{2} + 8 x + 5}} \]chain algebraApply the chain rule. Simplify the constant coefficient.✓ Proved
- \[ = \frac{3 \left(\frac{d}{d x} 5 + \frac{d}{d x} 8 x + \frac{d}{d x} 4 x^{2}\right)}{4 \sqrt{4 x^{2} + 8 x + 5}} \]sumDifferentiate the sum term by term.✓ Proved
- \[ = \frac{3 \left(8 x + 8\right)}{4 \sqrt{4 x^{2} + 8 x + 5}} \]derivative simplifyCalculate the derivatives of each term. Simplify the derivative of the polynomial.✓ Proved
- \[ = \frac{6 x + 6}{\sqrt{4 x^{2} + 8 x + 5}} \]algebra simplifyMove the negative exponent to the denominator. Distribute the constant and simplify the final expression.✓ Proved
Answer \( \frac{6 \left(x + 1\right)}{\sqrt{4 x^{2} + 8 x + 5}} \)
✓ 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 4*x**2 + 8*x + 5 = 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*x + 5 = 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 undefined where 4*x**2 + 8*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
Every verdict on record (4)
qwen3.6:27b-mlx: pass 2026-10-05gpt-oss:20b: pass 2026-10-05qwen3.6:27b-mlx: pass 2026-10-05gpt-oss:20b: pass 2026-10-05
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 2026-10-05 with SymPy 1.14.0.