Math Problem Statement

Find the domain and range of the function

Solution

The function provided is:

f(x)=x4x225f(x) = \frac{\sqrt{x - 4}}{x^2 - 25}

To find the domain and range of this function, let's analyze it step by step:

Domain:

The domain consists of all values of xx for which the function is defined.

  1. Square Root Condition: The expression under the square root, x4x - 4, must be non-negative: x40    x4.x - 4 \geq 0 \implies x \geq 4.

  2. Denominator Condition: The denominator x225x^2 - 25 cannot be zero: x2250    x±5.x^2 - 25 \neq 0 \implies x \neq \pm 5.

So, the function is defined for x4x \geq 4, except when x=5x = 5. Therefore, the domain is: x[4,5)(5,).x \in [4, 5) \cup (5, \infty).

Range:

For the range, we need to consider how the function behaves for the allowed values of xx.

  1. As x4+x \to 4^+, x4\sqrt{x - 4} approaches 0, so f(x)f(x) tends to 0 (but does not actually reach 0 since x225x^2 - 25 is non-zero).

  2. As xx increases beyond 5, both x4\sqrt{x - 4} and x225x^2 - 25 increase. However, since the denominator grows faster than the numerator, f(x)f(x) approaches 0 from above as xx \to \infty.

Given these behaviors, the range of f(x)f(x) is: f(x)(0,).f(x) \in (0, \infty).

Conclusion:

  • Domain: [4,5)(5,)[4, 5) \cup (5, \infty)
  • Range: (0,)(0, \infty)

Would you like more details or have any questions?

Here are 5 related questions for further exploration:

  1. How does the discontinuity at x=5x = 5 affect the graph of the function?
  2. What is the behavior of the function near the critical points x=4x = 4 and x=5x = 5?
  3. How would you determine if this function is continuous or differentiable over its domain?
  4. Can you find the asymptotes of this function?
  5. How does the graph of this function compare to simpler rational functions?

Tip: When determining the domain of a function involving square roots and rational expressions, always check for both non-negative conditions under the root and restrictions due to denominators.

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Math Problem Analysis

Mathematical Concepts

Functions
Domain and Range
Rational Functions
Square Roots

Formulas

None

Theorems

None

Suitable Grade Level

Grades 11-12