The function [tex]f(x) = \frac{5}{4} (\frac{4}{5}) ^{x}[/tex] represents the stretch of an exponential decay function.
What is exponential decay function?
The process of reducing an amount by a consistent percentage rate over a period of time. It can be expressed by the formula [tex]y = a(1-b)^{x}[/tex]
where,
y is the final amount,
a is the original amount,
(1 -b) is the decay factor,
and x is the amount of time that has passed.
For a exponential decay function (1-b) is always less than 1. If (1-b) < 1 it represents the exponential growth function.
And if a < 1, then it represents vertical compression and if a > 1, then it represents vertical stretch.
According to given question.
We have some functions in which we have to find the which one represents the decay function.
According to the function
[tex]f(x) = \frac{4}{5}(\frac{5}{4} )^{x} }[/tex]
For the decay function, the decay factor will always less than 1. In the above function the decay factor [tex]\frac{5}{4}[/tex] i.e. 1.25 is greater than 1.
Therefore, the above function doesn't represent decay function.
[tex]f(x) = \frac{4}{5}( \frac{4}{5} )^{x}[/tex]
Here, a < 1 i.e. [tex]\frac{4}{5}[/tex] is less than 1 so the given function is not a stretch of an exponential decay function.
[tex]f(x) = \frac{5}{4} (\frac{4}{5}) ^{x}[/tex]
Here, b < 1 so it represents the exponential decay function. Also a > 1.
Therefore, the given function is the stretch of an exponential decay function.
[tex]f(x) = \frac{5}{4} (\frac{5}{4}) ^{x}[/tex]
Here, a > 1 but b > 1. Therefore, the above function doesn't represent the exponential decay function. It represents the exponential growth function.
Find out more information about exponential decay function here:
https://brainly.com/question/14355665
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