Which of these values for [tex]$P$[/tex] and [tex]$a$[/tex] will cause the function [tex]$f(x) = P a^x$[/tex] to be an exponential growth function?

A. [tex]$P = 5 ; a = 1$[/tex]
B. [tex]$P = \frac{1}{5} ; a = 2$[/tex]
C. [tex]$P = \frac{1}{5} ; a = \frac{1}{2}$[/tex]
D. [tex]$P = 5 ; a = \frac{1}{2}$[/tex]



Answer :

To determine which of the values for [tex]\( P \)[/tex] and [tex]\( a \)[/tex] will cause the function [tex]\( f(x) = P \cdot a^x \)[/tex] to be an exponential growth function, we need to understand the conditions for exponential growth.

For a function [tex]\( f(x) = P \cdot a^x \)[/tex] to represent exponential growth:
- The base [tex]\( a \)[/tex] must be greater than 1.
- The parameter [tex]\( P \)[/tex] can be any non-zero constant.

Let's examine each option by checking the value of [tex]\( a \)[/tex]:

Option A: [tex]\( P = 5; a = 1 \)[/tex]
- Here, [tex]\( a = 1 \)[/tex].
- Since [tex]\( a \)[/tex] is not greater than 1, this function will not exhibit exponential growth.

Option B: [tex]\( P = \frac{1}{5}; a = 2 \)[/tex]
- Here, [tex]\( a = 2 \)[/tex].
- Since [tex]\( a > 1 \)[/tex], this function will exhibit exponential growth regardless of the value of [tex]\( P \)[/tex], as long as [tex]\( P \neq 0 \)[/tex].

Option C: [tex]\( P = \frac{1}{5}; a = \frac{1}{2} \)[/tex]
- Here, [tex]\( a = \frac{1}{2} \)[/tex].
- Since [tex]\( a < 1 \)[/tex], this function will represent exponential decay, not growth.

Option D: [tex]\( P = 5; a = \frac{1}{2} \)[/tex]
- Here, [tex]\( a = \frac{1}{2} \)[/tex].
- Since [tex]\( a < 1 \)[/tex], this function will also represent exponential decay, not growth.

After evaluating all options, we conclude that the function [tex]\( f(x) = P \cdot a^x \)[/tex] will be an exponential growth function for:

Option B: [tex]\( P = \frac{1}{5}; a = 2 \)[/tex]