Math Problem Statement

explain each and every step

Find the domain and range of the following function: f(x) = √(2x − 6)

Solution

The function given in the image is f(x)=2x6f(x) = \sqrt{2x - 6}. The task is to find the domain and range of this function.

Step 1: Finding the Domain

The domain of a function is the set of all possible input values (i.e., xx values) for which the function is defined. Since f(x)f(x) involves a square root, the expression inside the square root must be non-negative (greater than or equal to zero) because the square root of a negative number is not defined in the set of real numbers.

The expression inside the square root is 2x62x - 6. To ensure this expression is non-negative, set up the inequality:

2x602x - 6 \geq 0

Step 2: Solving the Inequality

Now, solve the inequality 2x602x - 6 \geq 0:

  1. Add 6 to both sides to isolate the term with xx:

2x62x \geq 6

  1. Divide both sides by 2 to solve for xx:

x3x \geq 3

This inequality shows that xx must be greater than or equal to 3. Therefore, the domain of the function is all real numbers xx such that x3x \geq 3.

Domain Conclusion:

Domain=[3,)\text{Domain} = [3, \infty) This means xx can be any value from 3 to infinity.

Step 3: Finding the Range

The range of a function is the set of all possible output values (i.e., f(x)f(x) values) the function can produce.

For the function f(x)=2x6f(x) = \sqrt{2x - 6}:

  1. Since the square root function always produces non-negative values (i.e., y0\sqrt{y} \geq 0 for any y0y \geq 0), f(x)f(x) must be greater than or equal to 0.

  2. To find the minimum value of f(x)f(x), consider the smallest xx in the domain. The smallest xx value is 3 (from the domain). Substituting x=3x = 3 into the function gives:

f(3)=2(3)6=66=0=0f(3) = \sqrt{2(3) - 6} = \sqrt{6 - 6} = \sqrt{0} = 0

Thus, the minimum value of f(x)f(x) is 0.

  1. As xx increases, the value inside the square root (2x6)(2x - 6) also increases, and so does the value of f(x)f(x). As xx approaches infinity, f(x)f(x) will also approach infinity.

Range Conclusion:

Range=[0,)\text{Range} = [0, \infty) This means f(x)f(x) can be any value from 0 to infinity.

Summary

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

Would you like more details or have any questions?


Here are five related questions you might explore:

  1. How would the domain and range change if the function were f(x)=2x+6f(x) = \sqrt{2x + 6}?
  2. What happens to the domain and range if the function is f(x)=2x+6f(x) = \sqrt{-2x + 6}?
  3. How can we determine the domain and range of a quadratic function?
  4. What are the effects of shifting or scaling the graph of f(x)=2x6f(x) = \sqrt{2x - 6}?
  5. How would you find the domain and range of a function involving a cube root?

Tip: When finding the domain of functions involving square roots, always ensure the expression under the square root is non-negative.

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Math Problem Analysis

Mathematical Concepts

Algebra
Functions
Square Roots
Inequalities

Formulas

f(x) = √(2x − 6)

Theorems

Square Root Function Properties

Suitable Grade Level

Grades 9-11