Question

At the beginning of a population study, a city had 390,000 people. Each year since, the population has grown by 1.1%.

Let t be the number of years since start of the study. Let y be the city's population.
Write an exponential function showing the relationship between y and t.

Answer 1

t=number of years since start of the study.

y=city´s population.

first year:

y=390,000+0.073(390,000)=390,000(1+0.073) (=418470)

Second year:

y=(390,000(1+0.073) + 0.073(390,000(1+0.073) =

=390,000(1+0.073) (1+0.073)

=390,000(1+0.073)²

(≈449,018.31)

Third year: if you calculate it you would have:

y=390,000(1+0.073)³

Fourth year: if you compute it you would have:

y=390,000 (1+0.073)⁴

t th year:

y=390,000(1+0.073)^t

Answer: y=390,000(1+0.073)^t

Explanation: