Which value of [tex]$x$[/tex] is in the domain of [tex]$f(x) = \sqrt{x} - 2$[/tex]?

A. [tex][tex]$x = -2$[/tex][/tex]
B. [tex]$x = 0$[/tex]
C. [tex]$x = 1$[/tex]
D. [tex][tex]$x = 2$[/tex][/tex]



Answer :

To determine which value of [tex]\( x \)[/tex] is in the domain of the function [tex]\( f(x) = \sqrt{x} - 2 \)[/tex], we need to consider the domain of the square root function, [tex]\( \sqrt{x} \)[/tex].

The square root function, [tex]\( \sqrt{x} \)[/tex], is defined only for [tex]\( x \geq 0 \)[/tex]. Therefore, [tex]\( f(x) = \sqrt{x} - 2 \)[/tex] is defined for [tex]\( x \geq 0 \)[/tex].

Let's analyze each given value:

- Option A: [tex]\( x = -2 \)[/tex]

Since the square root of a negative number is not defined in the set of real numbers, [tex]\( \sqrt{-2} \)[/tex] does not exist in the reals. Hence, [tex]\( x = -2 \)[/tex] is not in the domain of [tex]\( f(x) \)[/tex].

- Option B: [tex]\( x = 0 \)[/tex]

For [tex]\( x = 0 \)[/tex]:
[tex]\[ f(0) = \sqrt{0} - 2 = 0 - 2 = -2 \][/tex]
Thus, [tex]\( f(0) \)[/tex] is defined and [tex]\( x = 0 \)[/tex] is in the domain of [tex]\( f(x) \)[/tex].

- Option C: [tex]\( x = 1 \)[/tex]

For [tex]\( x = 1 \)[/tex]:
[tex]\[ f(1) = \sqrt{1} - 2 = 1 - 2 = -1 \][/tex]
Thus, [tex]\( f(1) \)[/tex] is defined and [tex]\( x = 1 \)[/tex] is in the domain of [tex]\( f(x) \)[/tex].

- Option D: [tex]\( x = 2 \)[/tex]

For [tex]\( x = 2 \)[/tex]:
[tex]\[ f(2) = \sqrt{2} - 2 \][/tex]
The exact value of [tex]\( \sqrt{2} \)[/tex] is approximately [tex]\( 1.414 \)[/tex], so:
[tex]\[ f(2) = 1.414 - 2 = -0.586 \text{ (approximately)} \][/tex]
Thus, [tex]\( f(2) \)[/tex] is defined and [tex]\( x = 2 \)[/tex] is in the domain of [tex]\( f(x) \)[/tex].

Now, summarizing our findings:
- [tex]\( x = -2 \)[/tex] is not in the domain.
- [tex]\( x = 0 \)[/tex] is in the domain.
- [tex]\( x = 1 \)[/tex] is in the domain.
- [tex]\( x = 2 \)[/tex] is in the domain.

Therefore, the values of [tex]\( x \)[/tex] that are in the domain of [tex]\( f(x) = \sqrt{x} - 2 \)[/tex] are:
[tex]\[ \boxed{0, 1, 2} \][/tex]