Question

Help please...
A bird species in danger of extinction has a population that is decreasing exponentially (A=A0e^kt). Five years ago , the population was at 1400 and today only 1000 of the birds are alive. Once the population drops below 100, the situation will be irreversible . When will this happen?

Answer 1

First solve for k using initial conditions
\[1000=1400e ^{5k}\]
Then solve for t using k found above
\[100=1400e ^{kt}\]

Answer 2

use natural log to cancel out the e