Determine the Domain of √(x²+2)/3

Question

Look at the following function:

x2+23 \frac{\sqrt{x^2+2}}{3}

What is the domain of the function?

Video Solution

Solution Steps

00:00 Does the function have a domain? If so, what is it?
00:03 The domain of the denominator is to avoid division by 0
00:08 Therefore, for the denominator there is no domain restriction, let's check the numerator
00:12 A square root must be of a positive number
00:17 Any number squared is necessarily greater than 0
00:23 Therefore, any positive number plus 2 will be positive
00:27 Therefore, all X values are valid, and this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll determine the domain of the function f(x)=x2+23 f(x) = \frac{\sqrt{x^2+2}}{3} .

First, consider the expression inside the square root, x2+2 x^2 + 2 . In order for the square root to be defined for real numbers, the expression x2+2 x^2 + 2 must be non-negative.

Let's analyze x2+2 x^2 + 2 :

  • For any real number x x , the expression x2 x^2 is always non-negative.
  • Adding 2 to x2 x^2 means x2+2 x^2 + 2 is always greater than or equal to 2.
  • Thus, x2+22>0 x^2 + 2 \geq 2 > 0 for all real numbers x x .

Since the value under the square root is always positive for all real numbers, the square root, and hence the function f(x) f(x) , is defined for all real numbers.

Therefore, the function has no restrictions on its domain other than the real number system itself. There are no variables in the denominator that can make it zero, as it is the constant 3.

Thus, the domain of the function is all real numbers.

The correct answer choice is: All real numbers.

Answer

All real numbers