A can of soda at temperature 25◦ C is placed in a refrigerator, where the ambient temperature F
is 10◦ C. We want to determine how the temperature of the soda changes over a period of time. A
standard way of approaching this type of problem is to subdivide the time interval into a number
of small steps, each of duration Δt. If Ti is the temperature at the beginning of step i, the following
model can be used to determine Ti+1: