How does [tex]$g(t)=5 \cdot 1.45^t$[/tex] change over the interval from [tex]$t=4$[/tex] to [tex][tex]$t=5$[/tex][/tex]?

A. [tex]g(t)[/tex] decreases by a factor of 1.45
B. [tex]g(t)[/tex] increases by a factor of 1.45
C. [tex]g(t)[/tex] increases by 145%
D. [tex]g(t)[/tex] decreases by 45%



Answer :

To determine how the function [tex]\( g(t) = 5 \cdot 1.45^t \)[/tex] changes over the interval from [tex]\( t = 4 \)[/tex] to [tex]\( t = 5 \)[/tex], we will follow these steps:

1. Calculate [tex]\( g(4) \)[/tex]:
[tex]\[ g(4) = 5 \cdot 1.45^4 \][/tex]
Given the result, [tex]\( g(4) \approx 22.10253125 \)[/tex].

2. Calculate [tex]\( g(5) \)[/tex]:
[tex]\[ g(5) = 5 \cdot 1.45^5 \][/tex]
Given the result, [tex]\( g(5) \approx 32.0486703125 \)[/tex].

3. Determine the ratio of [tex]\( g(t) \)[/tex] at [tex]\( t = 5 \)[/tex] to [tex]\( g(t) \)[/tex] at [tex]\( t = 4 \)[/tex]:
[tex]\[ \text{Ratio} = \frac{g(5)}{g(4)} = \frac{32.04867031249999}{22.10253125} \approx 1.45 \][/tex]

4. Convert this ratio to a percentage increase. Since the ratio is approximately [tex]\( 1.45 \)[/tex], we calculate the percentage increase as follows:
[tex]\[ \text{Percentage Increase} = (1.45 - 1) \times 100 = 0.45 \times 100 = 45\% \][/tex]

5. Interpret the result:
- The function [tex]\( g(t) \)[/tex] increases by a factor of [tex]\( 1.45 \)[/tex] from [tex]\( t = 4 \)[/tex] to [tex]\( t = 5 \)[/tex].
- Alternatively, we can say that [tex]\( g(t) \)[/tex] increases by [tex]\( 45\% \)[/tex] over this interval.
- Note that [tex]\( 145\% \)[/tex] represents a much greater increase and is not the correct interpretation.

Consequently, the correct interpretation for the change in [tex]\( g(t) \)[/tex] over the interval from [tex]\( t = 4 \)[/tex] to [tex]\( t = 5 \)[/tex] is:

[tex]\[ \boxed{\text{g(t) increases by a factor of 1.45}} \][/tex]