
6 Optimization: Algorithms and Applications
D
c
c P
=
+
1
2
2
(1.5)
where c
1
and c
2
are constants.
Some problems can be written mathematically in differential equation form.
A differential equation contains an unknown function and its derivatives.
As the derivative represents the rate of change of a function, the differen-
tial equation represents the continuously varying quantity and its rate of
change. For example, the temperature change (with respect to time) of an
object is proportional to the difference between the temperature (T) of the
object and that of its surroundings (T
s
) and can be represented in differential
equation form as
dT
k T