What are the domain, range, and asymptote of [tex]$h(x) = (0.5)^x - 9$[/tex]?

A. Domain: [tex]\{x \mid x \ \textgreater \ 9\}[/tex]; Range: [tex]\{y \mid y \text{ is a real number}\}[/tex]; Asymptote: [tex]y = 9[/tex]

B. Domain: [tex]\{x \mid x \ \textgreater \ -9\}[/tex]; Range: [tex]\{y \mid y \text{ is a real number}\}[/tex]; Asymptote: [tex]y = -9[/tex]

C. Domain: [tex]\{x \mid x \text{ is a real number}\}[/tex]; Range: [tex]\{y \mid y \ \textgreater \ 9\}[/tex]; Asymptote: [tex]y = 9[/tex]

D. Domain: [tex]\{x \mid x \text{ is a real number}\}[/tex]; Range: [tex]\{y \mid y \ \textgreater \ -9\}[/tex]; Asymptote: [tex]y = -9[/tex]



Answer :

To determine the domain, range, and asymptote of the function [tex]\( h(x) = (0.5)^x - 9 \)[/tex], let’s break it down step-by-step.

1. Domain:

The domain of a function is all the possible values that [tex]\( x \)[/tex] can take. In the function [tex]\( h(x) = (0.5)^x - 9 \)[/tex], there are no restrictions on [tex]\( x \)[/tex] because [tex]\( (0.5)^x \)[/tex] is defined for all real numbers. Thus, the domain includes all real numbers.
[tex]\[ \text{Domain: } \{ x \mid x \text{ is a real number} \} \][/tex]

2. Range:

The range of a function is all the possible values that [tex]\( h(x) \)[/tex] can take. The term [tex]\( (0.5)^x \)[/tex] represents an exponential decay function, which yields positive values for all real [tex]\( x \)[/tex]. As [tex]\( x \to -\infty \)[/tex], [tex]\( (0.5)^x \)[/tex] approaches [tex]\( +\infty \)[/tex]; and as [tex]\( x \to \infty \)[/tex], [tex]\( (0.5)^x \)[/tex] approaches [tex]\( 0 \)[/tex]. Subtracting 9 from [tex]\( (0.5)^x \)[/tex] shifts the entire graph down by 9 units.

This means that the lowest value [tex]\( h(x) \)[/tex] can approach is just slightly below -9 (but never reaching -9). Therefore, [tex]\( h(x) \)[/tex] will always be greater than -9.
[tex]\[ \text{Range: } \{ y \mid y > -9 \} \][/tex]

3. Asymptote:

An asymptote of a function is a line that the graph of the function approaches but never touches. For the function [tex]\( h(x) = (0.5)^x - 9 \)[/tex], as [tex]\( x \to \infty \)[/tex], [tex]\( (0.5)^x \)[/tex] approaches 0. Therefore, the function [tex]\( h(x) \)[/tex] approaches [tex]\( -9 \)[/tex]. This indicates a horizontal asymptote at [tex]\( y = -9 \)[/tex].
[tex]\[ \text{Asymptote: } y = -9 \][/tex]

Now, let's match our results with the given choices:

- Domain: [tex]\( \{ x \mid x \text{ is a real number} \} \)[/tex]
- Range: [tex]\( \{ y \mid y > -9 \} \)[/tex]
- Asymptote: [tex]\( y = -9 \)[/tex]

The correct answer matches our findings:
[tex]\[ \boxed{\text{domain: } \{ x \mid x \text{ is a real number} \}; \text{ range: } \{ y \mid y > -9 \}; \text{ asymptote: } y = -9} \][/tex]