Integral of \( \displaystyle \sqrt{2 x - 1} \)
Problem 4.654 · medium
Find \( \displaystyle \int \sqrt{2 x - 1} \, dx \). (Omit the constant of integration.)
- \[ \int \sqrt{2 x - 1}\, dx \]integral algebraStart with the integral of the function. Rewrite the square root as a fractional exponent.✓ Proved
- \[ = \int \sqrt{2} \sqrt{x - \frac{1}{2}}\, dx \]algebraFactor out the constant 2 from the expression inside the power.✓ Proved
- \[ = \sqrt{2} \int \sqrt{x - \frac{1}{2}}\, dx \]linearityMove the constant coefficient outside the integral.✓ Proved
- \[ = \frac{2 \sqrt{2} \left(x - \frac{1}{2}\right)^{\frac{3}{2}}}{3} \]antiderivative algebra algebraApply the power rule for integration. Simplify the fraction 1/(3/2) to 2/3. Rewrite (x - 1/2) as (2*x - 1)/2.✓ Proved
- \[ = \frac{\left(2 x - 1\right)^{\frac{3}{2}}}{3} \]algebra algebra algebra simplifyDistribute the exponent 3/2 to the numerator and denominator. Group the powers of 2 in the denominator. Simplify the exponent subtraction 3/2 - 1/2 = 1. Simplify the coefficient 2/3 / 2 to 1/3.✓ Proved
Answer \( \frac{\left(2 x - 1\right)^{\frac{3}{2}}}{3} + C \)
✓ 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 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 6 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 7 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 8 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 9 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 10 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| 11 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 |
| answer | ✓ Proved | sympy 1.14.0 | final line against the stated answer: simplify(a - b) reduced to 0 |
| answer, a second way | ✓ Proved | sympy 1.14.0 | SymPy differentiated the stated antiderivative back to the integrand |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: fail (style) — Step 3 applies two algebraic rules at once: factoring out the constant 2 and rewriting the term inside the power, violating the one-rule-per-step constraint. A simpler substitution in Step 5 would also have avoided the complex algebraic manipulation in Steps 3-11.
Every verdict on record (4)
gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: fail (style) 2026-10-08 — Step 3 applies two algebraic rules at once: factoring out the constant 2 and rewriting the term inside the power, violating the one-rule-per-step constraint. A simpler substitution in Step 5 would also have avoided the complex algebraic manipulation in Steps 3-11.gpt-oss:20b: pass 2026-10-08qwen3.6:27b-mlx: pass 2026-10-08 — The solution correctly applies algebraic manipulation and the power rule for integration. Each step changes only one aspect of the expression and uses valid labels from the fixed vocabulary.
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 2026-10-08 with SymPy 1.14.0.