College

What is the rate of decay, [tex] r [/tex] (expressed as a decimal), for data best modeled by the exponential function [tex] y = 63.4(0.92)^x [/tex]?

A. [tex] r = 36.6 [/tex]
B. [tex] r = 0.92 [/tex]
C. [tex] r = 0.08 [/tex]
D. [tex] r = 63.4 [/tex]

Answer :

To find the rate of decay, we need to look at the exponential function provided, which is [tex]\( y = 63.4(0.92)^x \)[/tex].

In an exponential function of the form [tex]\( y = A(b)^x \)[/tex], where [tex]\( A \)[/tex] is the initial amount and [tex]\( b \)[/tex] is the base:

1. If [tex]\( b > 1 \)[/tex], the function represents exponential growth.
2. If [tex]\( 0 < b < 1 \)[/tex], the function represents exponential decay.

The base [tex]\( b \)[/tex] in the given function is 0.92. Since 0.92 is less than 1, we are dealing with decay.

The rate of decay [tex]\( r \)[/tex] is calculated using the formula:

[tex]\[ r = 1 - b \][/tex]

So, plug in the value of [tex]\( b \)[/tex]:

[tex]\[ r = 1 - 0.92 = 0.08 \][/tex]

Therefore, the rate of decay [tex]\( r \)[/tex] is 0.08.