P = A e^kt
A = 5 is given when t = 0 (because e^0 = 1)
P = 5 e^kt
310 = 5 e^5k
62 = e^5k
ln 62 = 5 k
5 k = 4.127
k = .8254
so
P = 5 e^.8254 t
now if P = 1,000
200 = e^.8254 t
ln 200 = 5.298 = .8254 t
t = 6.42 years
(a) Express the population of the colony of rabbits, P , as a function of time, t , in years.
(b) Use the graph to estimate how long it takes for the population of rabbits to reach 1000 rabbits.
A = 5 is given when t = 0 (because e^0 = 1)
P = 5 e^kt
310 = 5 e^5k
62 = e^5k
ln 62 = 5 k
5 k = 4.127
k = .8254
so
P = 5 e^.8254 t
now if P = 1,000
200 = e^.8254 t
ln 200 = 5.298 = .8254 t
t = 6.42 years
So, we have Pā = 5 and P = 310. Let's solve for k!
310 = 5 * e^(k * 5)
Divide both sides by 5:
62 = e^(5k)
Now take the natural logarithm of both sides:
ln(62) = 5k
Finally, divide both sides by 5:
k = ln(62)/5
Now we have k, we can plug it back into the equation to find the population as a function of time!
P = 5 * e^[(ln(62)/5) * t]
(b) Now, estimating how long it takes for the population of rabbits to reach 1000 rabbits, let's plug in P = 1000 and solve for t:
1000 = 5 * e^[(ln(62)/5) * t]
Divide both sides by 5:
200 = e^[(ln(62)/5) * t]
Take the natural logarithm of both sides:
ln(200) = (ln(62)/5) * t
Now, divide both sides by ln(62)/5:
t = ln(200) / (ln(62) / 5)
Plug this equation into a calculator, and you'll get your estimated time! Just remember, rabbits can be unpredictable, so this is just an estimate. Don't be hopping mad if it's not exact!
P(t) = P0 * e^(rt)
where P0 is the initial population, r is the growth rate, and e is the base of the natural logarithm.
(a) We know that the colony begins with 5 rabbits, so P0 = 5. We also know that 5 years later there are 310 rabbits. So, we can use this information to find the value of r.
P(5) = 310
5 = 5 * e^(5r)
Divide both sides by 5 to isolate the exponential term:
1 = e^(5r)
Take the natural logarithm (ln) of both sides to solve for r:
ln(1) = ln(e^(5r))
0 = 5r
Divide both sides by 5 to find r:
0 = r
So, the growth rate, r, is 0.
Now that we have the growth rate, we can express the population of the colony of rabbits as a function of time:
P(t) = 5 * e^(0 * t)
P(t) = 5
The population will remain constant at 5 rabbits over time.
(b) Since the population remains constant at 5 rabbits, it will never reach 1000. Therefore, it would take an infinite amount of time for the population of rabbits to reach 1000.
P(t) = P0 * e^(kt)
Where:
P(t) = population at time t
P0 = initial population
k = growth rate
e = base of the natural logarithm (approximately 2.718)
In this case, the initial population is 5 rabbits and it grows to 310 rabbits after 5 years.
We can use this information to solve for k in the exponential growth formula.
310 = 5 * e^(5k)
To solve for k, we can divide both sides by 5 and take the natural logarithm of both sides:
62 = e^(5k)
ln(62) = 5k
Now we can solve for k,
k = ln(62) / 5 ā 0.970
Now we can write the function to express the population of the colony of rabbits as a function of time:
P(t) = 5 * e^(0.970t)
To estimate how long it takes for the population of rabbits to reach 1000, we can use the equation P(t) = 1000 and solve for t:
1000 = 5 * e^(0.970t)
Dividing both sides by 5:
200 = e^(0.970t)
Taking the natural logarithm of both sides:
ln(200) = 0.970t
Now we can solve for t,
t = ln(200) / 0.970 ā 5.44
Therefore, it takes approximately 5.44 years for the population of rabbits to reach 1000.