Expression Limit
1. Let's state the problem: We want to analyze the expression $$\frac{2n^2 - 3}{n^2 + 3}$$ and explain why this expression is limited (bounded).
2. First, observe the expression's numerator and denominator:
- Numerator: $$2n^2 - 3$$
- Denominator: $$n^2 + 3$$
3. Since $$n^2$$ is always non-negative for all real $$n$$, the denominator $$n^2 + 3$$ is always positive and never zero. This means the expression is defined for all real $$n$$.
4. To understand if the expression is limited (bounded), we analyze the behavior as $$|n|$$ becomes very large (goes to infinity). The highest degree terms dominate:
$$\frac{2n^2 - 3}{n^2 + 3} \approx \frac{2n^2}{n^2} = 2$$
5. Next, let's consider the precise form by dividing numerator and denominator by $$n^2$$ (assuming $$n \neq 0$$):
$$\frac{2n^2 - 3}{n^2 + 3} = \frac{2 - \frac{3}{n^2}}{1 + \frac{3}{n^2}}$$
6. As $$n \to \pm \infty$$, $$\frac{3}{n^2} \to 0$$, so the expression approaches:
$$\frac{2 - 0}{1 + 0} = 2$$
7. To check if the expression can take values beyond some bounds, simplify the expression differently. Let's denote $$y = \frac{2n^2 - 3}{n^2 + 3}$$.
8. Solve for $$n^2$$ in terms of $$y$$:
$$y(n^2 + 3) = 2n^2 - 3$$
$$y n^2 + 3y = 2n^2 - 3$$
$$2n^2 - y n^2 = 3y + 3$$
$$(2 - y) n^2 = 3(y + 1)$$
$$n^2 = \frac{3(y + 1)}{2 - y}$$
9. For $$n^2$$ to be real and non-negative, the right side must be $$\geq 0$$:
$$\frac{3(y + 1)}{2 - y} \geq 0$$
10. Analyze the inequality for $$y$$:
- Numerator: $$3(y + 1)$$ has the same sign as $$y + 1$$.
- Denominator: $$2 - y$$ has the same sign as $$2 - y$$.
11. The fraction is non-negative when numerator and denominator share the same sign:
- Case 1: $$y + 1 \geq 0$$ and $$2 - y > 0$$
$$y \geq -1$$ and $$y < 2$$
- Case 2: $$y + 1 \leq 0$$ and $$2 - y < 0$$
$$y \leq -1$$ and $$y > 2$$ which is impossible
12. Therefore, $$y$$ must satisfy $$-1 \leq y < 2$$.
13. Conclusion: The expression $$\frac{2n^2 - 3}{n^2 + 3}$$ is limited/bounded between $$-1$$ and $$2$$, never reaching $$2$$ but approaching it asymptotically, and attaining $$-1$$ at some points.
14. This boundedness occurs because numerator and denominator are quadratic polynomials with leading terms of the same degree, and the limits of the quotient are finite as $$n$$ grows large.
Final answer: The expression is limited because its values lie in the range $$-1 \leq \frac{2n^2 - 3}{n^2 + 3} < 2$$.