Determining the Domain of 4/√(x+8): A Function Analysis

Question

Look at the following function:

4x+8 \frac{4}{\sqrt{x+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?
00:03 The root must be for a positive number greater than 0
00:10 Let's isolate X
00:13 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we need to determine the domain of the function given by:

f(x)=4x+8 f(x) = \frac{4}{\sqrt{x+8}}

We must ensure that the function is defined for all x x . This involves considering the conditions under which the square root is valid and the denominator is non-zero.

Step 1: Analyze the square root expression x+8 \sqrt{x+8} . The expression inside the square root must be non-negative:

x+80 x + 8 \ge 0

Step 2: Solve the inequality:

  • Subtract 8 from both sides: x8 x \ge -8

Step 3: Consider the division by zero issue. The denominator x+8\sqrt{x+8} must be strictly greater than zero to avoid division by zero. Thus, we adjust the inequality to:

x+8>0 x + 8 > 0

Step 4: Solve the second inequality:

  • Subtract 8 from both sides: x>8 x > -8

Thus, the domain of the function is all x x such that x>8 x > -8 .

Review of the answer choices shows that the correct choice, consistent with our findings, is:

x>8 x > -8

Therefore, the domain of the function is x>8 x > -8 .

Answer

x > -8