Math Problem Statement

Find the factors that are common in the numerator and the denominator. Then find the intercepts and asymptotes. (If an answer does not exist, enter DNE. Enter your asymptotes as a comma-separated list of equations if necessary.) r(x) = x3 − 1x2 − 2x x − 2

Solution

Let's begin by simplifying the given function and then find the common factors, intercepts, and asymptotes.

Given function:

r(x)=x3x22xx2r(x) = \frac{x^3 - x^2 - 2x}{x - 2}

Step 1: Factor the numerator

We have: x3x22xx^3 - x^2 - 2x Factor out the common factor of xx: x(x2x2)x(x^2 - x - 2) Now, factor x2x2x^2 - x - 2 further: x2x2=(x2)(x+1)x^2 - x - 2 = (x - 2)(x + 1) Thus, the numerator becomes: x(x2)(x+1)x(x - 2)(x + 1) Now the function is: r(x)=x(x2)(x+1)x2r(x) = \frac{x(x - 2)(x + 1)}{x - 2}

Step 2: Cancel out the common factor

We notice that both the numerator and the denominator have the factor x2x - 2, so we can cancel it out: r(x)=x(x+1)r(x) = x(x + 1) However, we must remember that x=2x = 2 is a point of discontinuity because it was cancelled, so there is a hole at x=2x = 2.

Step 3: Find the intercepts

x-intercepts:

The x-intercepts occur when r(x)=0r(x) = 0. Set the numerator equal to zero: x(x+1)=0x(x + 1) = 0 Solve for xx: x=0orx=1x = 0 \quad \text{or} \quad x = -1 Thus, the x-intercepts are at x=0x = 0 and x=1x = -1.

y-intercept:

To find the y-intercept, set x=0x = 0: r(0)=0(0+1)=0r(0) = 0(0 + 1) = 0 Thus, the y-intercept is at (0,0)(0, 0).

Step 4: Asymptotes

Vertical Asymptote:

A vertical asymptote occurs when the denominator equals zero, and the factor is not cancelled. The denominator is x2x - 2, which would be zero at x=2x = 2. Since this factor was cancelled, there is no vertical asymptote at x=2x = 2, but there is a hole at x=2x = 2.

Horizontal Asymptote:

As xx \to \infty or xx \to -\infty, the degree of the numerator and denominator are both the same (degree 2 after simplification). The behavior of the function is dominated by the highest-degree term in both the numerator and denominator: r(x)=x(x+1)x2asx or xr(x) = x(x + 1) \approx x^2 \quad \text{as} \quad x \to \infty \text{ or } x \to -\infty Since the degree of the numerator is higher than the denominator, there is no horizontal asymptote. Instead, the function increases without bound.

Summary of Results:

  • Common factors: x2x - 2 is the common factor that gets cancelled.
  • Intercepts:
    • x-intercepts: x=0x = 0 and x=1x = -1
    • y-intercept: (0,0)(0, 0)
  • Asymptotes:
    • Vertical asymptote: None (but a hole at x=2x = 2).
    • Horizontal asymptote: None.

Let me know if you would like more details or have further questions!

Related Questions:

  1. How do you factor cubic polynomials like x3x22xx^3 - x^2 - 2x?
  2. What is the significance of the hole in the graph of a function?
  3. Can a function have a vertical asymptote and a hole at the same point?
  4. How do you find the horizontal asymptote of rational functions?
  5. How does simplifying a rational expression affect its graph?

Tip: Always remember that after canceling a factor, check if that factor causes any discontinuity (like a hole), even if it's no longer in the simplified function.

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Factorization
Intercepts
Asymptotes

Formulas

x-intercepts: Set numerator = 0
y-intercept: Set x = 0
Vertical Asymptote: Set denominator = 0 (if factor not cancelled)
Horizontal Asymptote: Degree comparison of numerator and denominator

Theorems

Factor Theorem
Rational Function Asymptote Theorem

Suitable Grade Level

Grades 9-12