Math Problem Statement

find the range of f(x) = 2 / (x^2 - 16)?

Solution

To find the range of the function f(x)=2x216f(x) = \frac{2}{x^2 - 16}, we will follow a systematic approach:

Step 1: Identify the domain

First, we need to consider the values of xx for which the denominator is non-zero. The denominator is x216x^2 - 16, so we set it equal to zero to find the points where the function is undefined:

x216=0x^2 - 16 = 0

x2=16x^2 = 16

x=±4x = \pm 4

Thus, f(x)f(x) is undefined at x=4x = 4 and x=4x = -4, which means the domain of f(x)f(x) is x(,4)(4,4)(4,)x \in (-\infty, -4) \cup (-4, 4) \cup (4, \infty).

Step 2: Analyze the behavior of f(x)f(x)

Next, let's examine the function's behavior as xx approaches the values where it is undefined (i.e., x=4x = 4 and x=4x = -4):

  • As x4x \to 4, the denominator x216x^2 - 16 approaches 0 from the positive side, making f(x)f(x) approach ++\infty.
  • As x4x \to -4, the denominator x216x^2 - 16 also approaches 0 from the positive side, so f(x)f(x) approaches ++\infty.

As x|x| \to \infty, the denominator x216x^2 - 16 grows large, causing f(x)f(x) to approach 0 from the positive side. Therefore, f(x)0+f(x) \to 0^+ as x±x \to \pm \infty.

Step 3: Investigate the range

The function f(x)=2x216f(x) = \frac{2}{x^2 - 16} is always positive since x216x^2 - 16 is always positive for x>4|x| > 4. Thus, the range of f(x)f(x) must be positive values.

  • As x4±x \to 4^\pm or x4±x \to -4^\pm, f(x)f(x) \to \infty.
  • As x±x \to \pm \infty, f(x)0+f(x) \to 0^+, but never actually reaches 0.

Thus, the range of f(x)f(x) is (0,)(0, \infty).

Final Answer:

The range of f(x)=2x216f(x) = \frac{2}{x^2 - 16} is (0,)(0, \infty).


Would you like further clarification on any of these steps or additional examples? Here are some related questions for you:

  1. How do you find the range of a rational function?
  2. What happens to the range of a function if it has a vertical asymptote?
  3. How can you find the vertical asymptotes of rational functions like f(x)f(x)?
  4. How does the behavior of a function change when you shift the graph horizontally or vertically?
  5. How do you determine the horizontal asymptote of a rational function?

Tip: When finding the range of a rational function, look for points where the denominator can be zero (undefined points) and analyze the function’s behavior near these points.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Range of Functions
Asymptotes

Formulas

f(x) = 2 / (x^2 - 16)

Theorems

Behavior of rational functions near vertical asymptotes
Range of rational functions

Suitable Grade Level

Grades 9-12