Math Problem Statement

solve

Graph the rational function f(x) = 2 / (x - 1). Start by drawing the vertical and horizontal asymptotes. Then plot two points on each piece of the graph. Finally, click on the graph-a-function button.

Solution

To solve and graph the given rational function f(x)=2x1f(x) = \frac{2}{x-1}, we need to determine its key features: vertical asymptote, horizontal asymptote, and points on the graph.


Step 1: Vertical Asymptote

The vertical asymptote occurs where the denominator is zero because the function is undefined there.

Set x1=0x - 1 = 0:
x=1x = 1
Thus, there is a vertical asymptote at x=1x = 1.


Step 2: Horizontal Asymptote

For rational functions of the form P(x)Q(x)\frac{P(x)}{Q(x)}, where P(x)P(x) and Q(x)Q(x) are polynomials:

  • If the degrees of P(x)P(x) and Q(x)Q(x) are equal, the horizontal asymptote is given by the ratio of the leading coefficients.

Here:

  • The numerator 22 is degree 0 (constant), and the denominator x1x-1 is degree 1.

Since the degree of the denominator is greater than the numerator, the horizontal asymptote is:
y=0y = 0


Step 3: Plot Two Points

To plot points, choose values of xx on either side of the vertical asymptote x=1x = 1:

  1. When x=0x = 0: f(0)=201=2f(0) = \frac{2}{0 - 1} = -2 Point: (0,2)(0, -2)

  2. When x=2x = 2: f(2)=221=2f(2) = \frac{2}{2 - 1} = 2 Point: (2,2)(2, 2)

These points give you reference values on both sides of the asymptote.


Step 4: Draw the Graph

  • Draw the vertical asymptote x=1x = 1 as a dashed vertical line.
  • Draw the horizontal asymptote y=0y = 0 as a dashed horizontal line.
  • Plot the points (0,2)(0, -2) and (2,2)(2, 2).
  • Sketch the curve approaching the asymptotes as x1x \to 1^- and x1+x \to 1^+, and as x±x \to \pm\infty. The curve will look like two distinct branches.

Final Observations:

  • The curve decreases toward negative infinity as x1x \to 1^-.
  • The curve increases toward positive infinity as x1+x \to 1^+.
  • The graph levels off at y=0y = 0 as x±x \to \pm\infty.

Would you like me to explain how to sketch this step-by-step on the graph or provide further details?


Related Questions:

  1. How do you identify the vertical and horizontal asymptotes of any rational function?
  2. What happens when the degree of the numerator is larger than the denominator?
  3. How can you determine slant asymptotes for a rational function?
  4. Why are vertical asymptotes undefined at certain xx-values?
  5. How do you calculate intercepts for rational functions like this one?

Tip: Always test a few points on either side of the vertical asymptote to sketch a smooth curve!

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Asymptotes
Graphing Functions

Formulas

Vertical Asymptote: Set denominator = 0
Horizontal Asymptote: y = 0 if degree of numerator < degree of denominator

Theorems

Asymptote Behavior of Rational Functions
Graphing Rational Functions

Suitable Grade Level

Grades 9-11