Math Problem Statement

For each function f(x) = (x - 4) / (x^2 - 16) and g(x) = x / (x^2 + 1), find the domain. Write each answer as an interval or union of intervals.

Solution

To find the domain of each function f(x)f(x) and g(x)g(x), we need to identify the values of xx that make the denominator zero, as these values will be excluded from the domain.

1. Analyzing f(x)f(x):

The function f(x)f(x) is given by: f(x)=x4x216f(x) = \frac{x - 4}{x^2 - 16}

  1. Determine the denominator: The denominator is x216x^2 - 16.
  2. Set the denominator equal to zero: x216=0x^2 - 16 = 0 This factors as: (x4)(x+4)=0(x - 4)(x + 4) = 0 So, x=4x = 4 and x=4x = -4 are the values that make the denominator zero.
  3. Domain of f(x)f(x): Exclude x=4x = 4 and x=4x = -4 from the domain. Thus, the domain of f(x)f(x) in interval notation is: (,4)(4,4)(4,)(-\infty, -4) \cup (-4, 4) \cup (4, \infty)

2. Analyzing g(x)g(x):

The function g(x)g(x) is given by: g(x)=xx2+1g(x) = \frac{x}{x^2 + 1}

  1. Determine the denominator: The denominator is x2+1x^2 + 1.
  2. Set the denominator equal to zero: x2+1=0x^2 + 1 = 0 Solving for xx, we get: x2=1x^2 = -1 Since x2=1x^2 = -1 has no real solutions, the denominator is never zero for real numbers.
  3. Domain of g(x)g(x): The function g(x)g(x) is defined for all real values of xx. Therefore, the domain of g(x)g(x) is: (,)(-\infty, \infty)

Summary:

  • Domain of f(x)f(x): (,4)(4,4)(4,)(-\infty, -4) \cup (-4, 4) \cup (4, \infty)
  • Domain of g(x)g(x): (,)(-\infty, \infty)

Would you like a further breakdown of any steps?

Additional Questions

  1. What would the range of each function be?
  2. How would the domain change if we were dealing with complex numbers instead?
  3. What is the behavior of f(x)f(x) as xx approaches the excluded values?
  4. Can f(x)f(x) and g(x)g(x) be simplified further?
  5. How would the domain be affected if these functions were combined (e.g., f(x)+g(x)f(x) + g(x))?

Tip:

When determining the domain of a rational function, always start by identifying values that make the denominator zero, as these values are not included in the domain.

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Math Problem Analysis

Mathematical Concepts

Domain of Functions
Rational Functions
Factoring
Real Numbers

Formulas

Domain exclusion: Denominator cannot be zero

Theorems

Zero Product Property

Suitable Grade Level

Grades 11-12