Math Problem Statement

Find the domain and range of the following: (a). f(x) = 1/√(x − 3)

Solution

Let's analyze the function f(x)=1x3f(x) = \frac{1}{\sqrt{x - 3}} to determine its domain and range.

1. Domain:

The domain of a function is the set of all possible input values (x-values) for which the function is defined.

  • The expression under the square root, x3x - 3, must be non-negative because the square root of a negative number is not real. Therefore, we need: x30x - 3 \geq 0 x3x \geq 3

  • Additionally, the function f(x)f(x) involves a fraction, and the denominator x3\sqrt{x - 3} cannot be zero because division by zero is undefined. Therefore, we require: x30\sqrt{x - 3} \neq 0 x30x - 3 \neq 0 x3x \neq 3

Thus, combining these two conditions, the domain is: Domain of f(x):(3,)\text{Domain of } f(x): \, (3, \infty) This means f(x)f(x) is defined for all x>3x > 3.

2. Range:

The range of a function is the set of all possible output values (y-values).

  • f(x)=1x3f(x) = \frac{1}{\sqrt{x - 3}} is positive because both the numerator (1) and the square root function are positive for x>3x > 3.

  • As xx approaches 33 from the right (i.e., xx is slightly greater than 3), x3\sqrt{x - 3} approaches 0, and therefore, f(x)f(x) becomes very large. Thus, the function can take very large positive values.

  • As xx increases, x3\sqrt{x - 3} increases, making f(x)f(x) decrease. However, since the square root function increases without bound as xx increases, f(x)f(x) approaches 0 but never actually reaches 0.

Thus, the range of the function is: Range of f(x):(0,)\text{Range of } f(x): \, (0, \infty)

Summary:

  • Domain: (3,)(3, \infty)
  • Range: (0,)(0, \infty)

Would you like more details or have any questions?

Here are some related questions to consider:

  1. How would the domain change if the function were f(x)=15xf(x) = \frac{1}{\sqrt{5 - x}}?
  2. What is the domain and range of f(x)=x2f(x) = \sqrt{x - 2}?
  3. How does adding a constant inside the square root affect the domain and range?
  4. What is the domain and range of f(x)=1x21f(x) = \frac{1}{\sqrt{x^2 - 1}}?
  5. How would the range change if the function were f(x)=2x3f(x) = \frac{2}{\sqrt{x - 3}}?

Tip: Always remember that square roots require the radicand to be non-negative, and denominators cannot be zero!

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Math Problem Analysis

Mathematical Concepts

Functions
Square Roots
Domain and Range

Formulas

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Theorems

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Suitable Grade Level

High School