Which is an exponential growth function?

A. [tex]\( f(x) = 6(0.25)^x \)[/tex]
B. [tex]\( f(x) = 0.25(5.25)^x \)[/tex]
C. [tex]\( f(x) = -4.25^x \)[/tex]
D. [tex]\( f(x) = (-1.25)^x \)[/tex]



Answer :

To determine which of the given functions represents exponential growth, we need to examine the base of the exponential part of each function. An exponential growth function has a base greater than 1.

Let’s analyze each function:

1. [tex]\( f(x) = 6 (0.25)^x \)[/tex]

- The base of the exponent is [tex]\( 0.25 \)[/tex].
- Since [tex]\( 0.25 \)[/tex] is less than 1, this is an exponential decay function, not a growth function.

2. [tex]\( f(x) = 0.25 (5.25)^x \)[/tex]

- The base of the exponent is [tex]\( 5.25 \)[/tex].
- Since [tex]\( 5.25 \)[/tex] is greater than 1, this is an exponential growth function.

3. [tex]\( f(x) = -4.25^x \)[/tex]

- The base of the exponent is [tex]\( -4.25 \)[/tex].
- Since the base is negative, this does not represent a traditional exponential growth or decay function.

4. [tex]\( f(x) = (-1.25)^x \)[/tex]

- The base of the exponent is [tex]\( -1.25 \)[/tex].
- Despite being negative, this function can behave unpredictably depending on whether [tex]\( x \)[/tex] is an integer or not, and generally it's not considered exponential growth.

Among all the functions, the only function that has a base greater than 1 (which makes it an exponential growth function) is:

[tex]\[ f(x) = 0.25 (5.25)^x \][/tex]

Therefore, the exponential growth function is:
[tex]\[ f(x) = 0.25 (5.25)^x \][/tex]

The corresponding answer from the given choices is the second function. Hence, the answer is:

[tex]\[ f(x) = 0.25 (5.25)^x \][/tex]
This corresponds to choice 3.