Which statement describes the behavior of the function [tex]f(x)=\frac{2 x}{1-x^2}[/tex]?

A. The graph approaches -2 as [tex]x[/tex] approaches infinity.
B. The graph approaches 0 as [tex]x[/tex] approaches infinity.
C. The graph approaches 1 as [tex]x[/tex] approaches infinity.
D. The graph approaches 2 as [tex]x[/tex] approaches infinity.



Answer :

To determine the behavior of the function [tex]\( f(x) = \frac{2x}{1 - x^2} \)[/tex] as [tex]\( x \)[/tex] approaches infinity, we need to analyze the limit of the function when [tex]\( x \)[/tex] tends towards positive infinity ([tex]\( x \to \infty \)[/tex]).

Let's follow a step-by-step approach to find this limit:

1. Express the Function:
The function given is:
[tex]\[ f(x) = \frac{2x}{1 - x^2} \][/tex]

2. Simplify the Expression:
As [tex]\( x \)[/tex] becomes very large ([tex]\( x \to \infty \)[/tex]), the term [tex]\( x^2 \)[/tex] in the denominator dominates over the constant term 1, making [tex]\( 1 - x^2 \approx -x^2 \)[/tex]. So, the function can be approximated as:
[tex]\[ f(x) \approx \frac{2x}{-x^2} \][/tex]

3. Divide Numerator and Denominator by [tex]\( x \)[/tex]:
Simplify the approximation by dividing both the numerator and the denominator by [tex]\( x \)[/tex]:
[tex]\[ f(x) \approx \frac{2}{-x} = -\frac{2}{x} \][/tex]

4. Analyze the Limit:
Now we need to find the limit of [tex]\( -\frac{2}{x} \)[/tex] as [tex]\( x \)[/tex] approaches infinity:
[tex]\[ \lim_{x \to \infty} \left( -\frac{2}{x} \right) \][/tex]
As [tex]\( x \)[/tex] increases without bound, [tex]\( \frac{2}{x} \)[/tex] approaches 0. Therefore:
[tex]\[ \lim_{x \to \infty} \left( -\frac{2}{x} \right) = 0 \][/tex]

So, the limit of the function [tex]\( f(x) \)[/tex] as [tex]\( x \)[/tex] approaches infinity is 0. Hence, the graph of the function approaches 0 as [tex]\( x \)[/tex] tends towards infinity.

Thus, the correct statement is:
- The graph approaches 0 as [tex]\( x \)[/tex] approaches infinity.