Respuesta :
Answer:
- The formula its [tex]f(t) \ = \ - \ 352 \ \frac{\$ }{years} \ t \ + \ \$ \ 2816 [/tex]
- After 5 years, the computer value its $ 1056
Explanation:
Obtaining the formula
We wish to find a formula that
- Starts at 2816. [tex]f(0 \ years) \ = \ \$ \ 2816[/tex]
- Reach 0 at 8 years. [tex]f( 8 \ years) \ = \ \$ \ 0[/tex]
- Depreciates at a constant rate. m
We can cover all this requisites with a straight-line equation. (an straigh-line its the only curve that has a constant rate of change) :
[tex]f(t) \ = \ m\ t \ + \ b[/tex],
where m its the slope of the line and b give the place where the line intercepts the y axis.
So, we can use this formula with the data from our problem. For the first condition:
[tex]f ( 0 \ years ) = m \ (0 \ years) + b = \$ \ 2816[/tex]
[tex] b = \$ \ 2816[/tex]
So, b = $ 2816.
Now, for the second condition:
[tex]f ( 8 \ years ) = m \ (8 \ years) + \$ \ 2816 = \$ \ 0[/tex]
[tex] m \ (8 \ years) = \ - \$ \ 2816[/tex]
[tex] m = \frac{\ - \$ \ 2816}{8 \ years}[/tex]
[tex] m = \frac{\ - \$ \ 2816}{8 \ years}[/tex]
[tex] m = \ - \ 352 \frac{\$ }{years}[/tex]
So, our formula, finally, its:
[tex]f(t) \ = \ - \ 352 \ \frac{\$ }{years} \ t \ + \ \$ \ 2816 [/tex]
After 5 years
Now, we just use t = 5 years in our formula
[tex]f(5 \ years) \ = \ - \ 352 \ \frac{\$ }{years} \ 5 \ years \ + \ \$ \ 2816 [/tex]
[tex]f(5 \ years) \ = \ - \$ \ 1760 + \ \$ \ 2816 [/tex]
[tex]f(5 \ years) \ = $ \ 1056 [/tex]