Assume that the speed of new computers costing a certain amount of money grows exponentially over time, with the speed doubling every 18 months. Suppose you need to run a very time consuming program and are allowed to buy a new computer costing a fixed amount on which to run the program. If you start now, the program will take 7 years to finish. How long should you delay buying the computer and starting the program so that it will finish in the shortest amount of time from now

Respuesta :

Therefore, in order to run the program in the shortest time, you should delay for 3 years

Given that the speed of new computers costing a certain amount of money grows exponentially over time, with the speed doubling every 18 months.

Exponential equation as a function of time can be expressed as

P(t) = [tex]P_{0}[/tex][tex]R^{t/T}[/tex]

Quantity P will be increasing exponentially when R > 1. And it will decrease exponentially when R < 1.

Suppose you need to run a very time consuming program and are allowed to buy a new computer costing a fixed amount on which to run the program. If you start now, the program will take 7 years to finish.

Let the time required to run and complete a program for time t years be P(t).

If the speed doubling every 18 months, which is 3/2 years. This will eventually cause the running time to decrease by half (0.5)

P(t) = 7[tex](1/2)^{3t/2}[/tex] = 7[tex](2)^{-3t/2}[/tex]

The total time T will be sum of the delay time t and the time of running the program. That is

T(t) = t + P(t)

T(t) = t + 7[tex](2)^{-3t/2}[/tex]   .......... (2)

We can calculate the minimum time t by differentiating the above equation and make it equal to zero.

dT/dt = 1 + 14/3[tex](2)^{-3t/2}[/tex](ln0.5) = 0

14/3[tex](2)^{-3t/2}[/tex](ln0.5) = -1

[tex](2)^{-3t/2}[/tex](ln0.5) = -3/14

[tex](2)^{-3t/2}[/tex] = -3/14ln0.5

Log (natural logarithm) both sides

-3t/2ln2 = ln(3/14ln2)

make t the subject of formula

t = - 3ln(3/14ln2) ÷ 2ln2

t = 2.5 approximately

To know how long you should delay buying the computer and starting the program so that it will finish in the shortest amount of time from now, substitute t into equation 2

T(2.5) = 2.5 + (7)[tex]2^{-3(2.5)/2}[/tex]

T(2.5) = 2.5 + 0.5202

T(2.5) = 3.02 years

T (2.5) = 3 years approximately

Therefore, in order to run the program in the shortest time, you should delay for 3 years

Learn more here: https://brainly.com/question/6497099