Suppose that the dollar value [tex]\( v(t) \)[/tex] of a certain house that is [tex]\( t \)[/tex] years old is given by the following exponential function:
[tex]\[ v(t) = 532,000(0.77)^t \][/tex]

a) Find the initial value of the house. [tex]\(\square\)[/tex]

b) Does the function represent growth or decay?
- growth
- decay

c) By what percent does the value of the house change each year? [tex]\(\square\)[/tex] \%



Answer :

To solve the problem, let's go through it step-by-step:

1. Find the initial value of the house:

The given exponential function is:
[tex]\[ v(t) = 532,000 \cdot (0.77)^t \][/tex]
The initial value of the house is determined by evaluating the function at [tex]\( t = 0 \)[/tex]:
[tex]\[ v(0) = 532,000 \cdot (0.77)^0 = 532,000 \cdot 1 = 532,000 \][/tex]

Therefore, the initial value of the house is:
[tex]\[ \boxed{532,000} \][/tex]

2. Determine if the function represents growth or decay:

The factor being raised to the power of [tex]\( t \)[/tex] in the function is 0.77. Since this factor is less than 1, the function represents decay. Thus, the value of the house decreases over time.

Therefore, the function represents:
[tex]\[ \boxed{\text{decay}} \][/tex]

3. Calculate the percent change in the value of the house each year:

The decay rate is given by 0.77. To find the percent change per year, we first calculate how much the value of the house decreases each year:
[tex]\[ \text{Percent change} = (1 - \text{decay rate}) \times 100\% \][/tex]
In this case, the decay rate is 0.77:
[tex]\[ \text{Percent change} = (1 - 0.77) \times 100\% = 0.23 \times 100\% = 23\% \][/tex]

Therefore, the value of the house changes by:
[tex]\[ \boxed{23\%} \][/tex]
each year.