Answer:
A) 3%
B) Product A
Step-by-step explanation:
<u>Exponential Function</u>
General form of an exponential function: ![y=ab^x](https://tex.z-dn.net/?f=y%3Dab%5Ex)
where:
- a is the initial value (y-intercept)
- b is the base (growth/decay factor) in decimal form
- x is the independent variable
- y is the dependent variable
If b > 1 then it is an increasing function
If 0 < b < 1 then it is a decreasing function
<u>Part A</u>
<u>Product A</u>
Assuming the function for Product A is <u>exponential</u>:
![f(x) = 0.69(1.03)^x](https://tex.z-dn.net/?f=f%28x%29%20%3D%200.69%281.03%29%5Ex)
The base (b) is 1.03. As b > 1 then it is an <u>increasing function</u>.
To calculate the percentage increase/decrease, subtract 1 from the base:
⇒ 1.03 - 1 = 0.03 = 3%
Therefore, <u>product A is increasing by 3% each year.</u>
<u>Part B</u>
![\sf percentage\:change=\dfrac{final\:value-initial\:value}{initial\:value} \times 100](https://tex.z-dn.net/?f=%5Csf%20percentage%5C%3Achange%3D%5Cdfrac%7Bfinal%5C%3Avalue-initial%5C%3Avalue%7D%7Binitial%5C%3Avalue%7D%20%5Ctimes%20100)
To calculate the percentage change in Product B, use the percentage change formula with two consecutive values of f(t) from the given table:
![\implies \sf percentage\:change=\dfrac{10201-10100}{10100}\times 100=1\%](https://tex.z-dn.net/?f=%5Cimplies%20%5Csf%20percentage%5C%3Achange%3D%5Cdfrac%7B10201-10100%7D%7B10100%7D%5Ctimes%20100%3D1%5C%25)
Check using different two consecutive values of f(t):
![\implies \sf percentage\:change=\dfrac{10303.01-10201}{10201}\times 100=1\%](https://tex.z-dn.net/?f=%5Cimplies%20%5Csf%20percentage%5C%3Achange%3D%5Cdfrac%7B10303.01-10201%7D%7B10201%7D%5Ctimes%20100%3D1%5C%25)
Therefore, as 3% > 1%, <u>Product A recorded a greater percentage change</u> in price over the previous year.
Although the question has not asked, we can use the given information to easily create an exponential function for Product B.
Given:
- a = 10,100
- b = 1.01
- n = t - 1 (as the initial value is for t = 1 not t = 0)
![\implies f(t) = 10100(1.01)^{t-1}](https://tex.z-dn.net/?f=%5Cimplies%20f%28t%29%20%3D%2010100%281.01%29%5E%7Bt-1%7D)
To check this, substitute the values of t for 1 through 4 into the found function:
![\implies f(1) = 10100(1.01)^{1-1}=10100](https://tex.z-dn.net/?f=%5Cimplies%20f%281%29%20%3D%2010100%281.01%29%5E%7B1-1%7D%3D10100)
![\implies f(2) = 10100(1.01)^{2-1}=10201](https://tex.z-dn.net/?f=%5Cimplies%20f%282%29%20%3D%2010100%281.01%29%5E%7B2-1%7D%3D10201)
![\implies f(3) = 10100(1.01)^{3-1}=10303.01](https://tex.z-dn.net/?f=%5Cimplies%20f%283%29%20%3D%2010100%281.01%29%5E%7B3-1%7D%3D10303.01)
![\implies f(4) = 10100(1.01)^{4-1}=10406.04](https://tex.z-dn.net/?f=%5Cimplies%20f%284%29%20%3D%2010100%281.01%29%5E%7B4-1%7D%3D10406.04)
As these values match the values in the given table, this confirms that the found function for Product B is correct and that <u>Product B increases by 1% per year.</u>