Determining the Domain: Rational Function with a Square Root Denominator

Question

Look at the following function:

2x+22x8 \frac{2x+2}{\sqrt{2x-8}}

What is the domain of the function?

Video Solution

Solution Steps

00:00 Does the function have a domain? And if so, what is it?
00:04 A root must be for a positive number greater than 0
00:11 Let's isolate X
00:28 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we need to determine where the function f(x)=2x+22x8 f(x) = \frac{2x+2}{\sqrt{2x-8}} is defined.

For the fraction to be defined, the denominator cannot be zero, and for the square root to be defined, the radicand (the expression inside the square root) must be non-negative.

Therefore, we need to solve the inequality:

2x80 2x - 8 \geq 0

Solving this inequality involves the following steps:

  • Add 8 to both sides: 2x8 2x \geq 8
  • Divide both sides by 2: x4 x \geq 4

However, if x=4 x = 4 , the expression inside the square root is zero, making the denominator zero and the overall expression undefined.

As a result, the domain of the function is x>4 x > 4 .

Therefore, the domain of the function is x>4 x > 4 .

Answer

x > 4