Relative growth rate is
,
is a constant.
Initial relative growth rate is
, where
is initial value of
,
is change in
and
is change in
.
Initial growth rate is
.
Initial growth rate is
millions.
.
.
The initial population is
.
Substitute
,
and
in
.


.
Relative growth rate is
.
The logistic differential equation is
, where
is a carrying capacity.
Substitute
and
.
,
is in billions.
The logistic differential equation is
,
is in billions.
(b) Use the logistic model to estimate the world population in the year 2000 and compare with the actual population of 6.1
\billion.
\The logistic model equation is
, where
.
Substitute
and
in
.


.
Substitute
,
,
and
in
.
The logistic model equation is
.
The population in year
,
.
Substitute
in
.




.
The population in year
is
.
(c) Use the logistic model to predict the world population in the years 2100 and 2500.
\The logistic model equation is
.
The population in year
,
.
Substitute
in
.





.
The population in year
is
.
The population in year
,
.
Substitute
in
.




.
The population in year
is
.
(d) What are your predictions if the carrying capacity is 50 billion.
\The carrying capacity is
.
The logistic model equation is
, where
.
Substitute
and
in
.


.
Substitute
,
,
and
in
.
The logistic model equation is
.
The population in year
,
.
Substitute
in
.




.
The population in year
is
.
The population in year
,
.
Substitute
in
.





.
The population in year
is
.
The population in year
,
.
Substitute
in
.





.
The population in year
is
.
(a) The logistic differential equation is
,
is in billions.
(b) The population in year
is
.
(c)
\The population in year
is
.
The population in year
is
.
(d)
\The population in year
is
.
The population in year
is
.
The population in year
is
.