Math Problem Statement

solve

Solve and graph the function f(x) = -8 / (-x - 2), including vertical and horizontal asymptotes, and plot two points.

Solution

To solve the problem of graphing the function f(x)=8x2f(x) = \frac{-8}{-x - 2}, we will analyze the function step-by-step by identifying the asymptotes, key points, and sketching the graph.


Step 1: Rewrite the Function for Clarity

The given function is:

f(x)=8x2f(x) = \frac{-8}{-x - 2}

Simplify the denominator:

f(x)=8(x+2)=8x+2f(x) = \frac{-8}{-(x + 2)} = \frac{8}{x + 2}

Thus, the function becomes:

f(x)=8x+2f(x) = \frac{8}{x + 2}


Step 2: Identify the Vertical Asymptote

A vertical asymptote occurs when the denominator equals zero because division by zero is undefined. Set x+2=0x + 2 = 0:

x=2x = -2

So, the vertical asymptote is at x=2x = -2.


Step 3: Identify the Horizontal Asymptote

To determine the horizontal asymptote for a rational function:

  • Compare the degrees of the numerator and denominator.

Here, the numerator 88 is degree 00 (constant), and the denominator x+2x + 2 is degree 11 (linear).

When the degree of the denominator is greater than the degree of the numerator, the horizontal asymptote is:

y=0y = 0


Step 4: Plot Key Points

To sketch the graph, pick values of xx on either side of the vertical asymptote x=2x = -2.

For x=3x = -3:

f(3)=83+2=81=8f(-3) = \frac{8}{-3 + 2} = \frac{8}{-1} = -8 Point: (3,8)(-3, -8)

For x=1x = -1:

f(1)=81+2=81=8f(-1) = \frac{8}{-1 + 2} = \frac{8}{1} = 8 Point: (1,8)(-1, 8)


Step 5: Sketch the Graph

  1. Vertical asymptote at x=2x = -2.
  2. Horizontal asymptote at y=0y = 0.
  3. Plot the points (3,8)(-3, -8) and (1,8)(-1, 8) as reference points.

Step 6: Graph Behavior

  • As x2x \to -2^- (from the left), f(x)f(x) \to -\infty.
  • As x2+x \to -2^+ (from the right), f(x)f(x) \to \infty.
  • As x±x \to \pm \infty, f(x)0f(x) \to 0 (horizontal asymptote).

Final Answer

  1. Vertical asymptote: x=2x = -2
  2. Horizontal asymptote: y=0y = 0
  3. Plot points (3,8)(-3, -8) and (1,8)(-1, 8).

Would you like more explanation or further graphing help? Here are some related questions:


  1. How do you determine vertical asymptotes for rational functions?
  2. How do horizontal asymptotes depend on the degree of polynomials?
  3. What happens when a rational function has no horizontal asymptote?
  4. How do you identify points to graph rational functions accurately?
  5. What is the significance of asymptotes in real-world applications?

Tip: Always simplify the function first to make analysis easier!

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Asymptotes
Graphing Functions

Formulas

Vertical Asymptote: x = -d / c (from denominator roots)
Horizontal Asymptote: Compare degrees of numerator and denominator

Theorems

Asymptote Theorem for Rational Functions

Suitable Grade Level

Grades 10-12