Limit of \( \displaystyle \frac{6 x - 1}{\left(3 x - 1\right)^{2} + 3} \) as \( x \to \infty \)
Problem 1.323 · medium
Evaluate \( \displaystyle \lim_{x \to \infty} \frac{6 x - 1}{\left(3 x - 1\right)^{2} + 3} \).
- \[ \lim_{x \to \infty}\left(\frac{6 x - 1}{\left(3 x - 1\right)^{2} + 3}\right) \]limitStart with the limit of the given function as x approaches infinity.✓ Proved
- \[ = \lim_{x \to \infty}\left(\frac{6 x - 1}{9 x^{2} - 6 x + 4}\right) \]simplifyExpand the denominator.✓ Proved
- \[ = \lim_{x \to \infty}\left(\frac{\frac{6}{x} - \frac{1}{x^{2}}}{9 - \frac{6}{x} + \frac{4}{x^{2}}}\right) \]algebra simplifyDivide numerator and denominator by x**2. Simplify the fractions inside the limit.✓ Proved
- \[ = \lim_{x \to \infty} 0 \]limit-law simplifyEvaluate the limit of each term as x approaches infinity. Simplify the resulting fraction.✓ Proved
- \[ = 0 \]limitThe final value of the limit.✓ Proved
Answer \( 0 \)
✓ 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 undefined where (3*x - 1)**2 + 3 = 0 undefined where 9*x**2 - 6*x + 4 = 0 |
| 3 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 9*x**2 - 6*x + 4 = 0 undefined where 9 - 6/x + 4/x**2 = 0 undefined where x = 0 |
| 4 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 9 - 6/x + 4/x**2 = 0 undefined where x = 0 |
| 5 | ✓ Proved | sympy 1.14.0 | simplify(a - b) reduced to 0 undefined where 9 - 6/x + 4/x**2 = 0 undefined where x = 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 |
| 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 took the limit from both sides and got the stated value |
Reviewers
gpt-oss:20b: passqwen3.6:27b-mlx: pass — The solution correctly applies algebraic simplification and limit laws to evaluate the limit at infinity. Each step changes only one aspect of the expression and uses valid labels from the provided vocabulary.
Every verdict on record (4)
gpt-oss:20b: pass 2026-10-06qwen3.6:27b-mlx: pass 2026-10-06 — The solution correctly applies algebraic simplification and limit laws to evaluate the limit at infinity. Each step changes only one aspect of the expression and uses valid labels from the provided vocabulary.qwen3.6:27b-mlx: pass 2026-10-06 — The solution correctly expands the denominator, divides by the highest power of x, and evaluates the limit term-by-term. Each step applies a single rule and uses valid labels from the fixed vocabulary.gpt-oss:20b: pass 2026-10-06
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 2026-10-06 with SymPy 1.14.0.