The temperature T of a cup of coffee is a function T(t) where t is the time in minutes. The room temperature is 18° Celsius. The
rate at which the coffee cools down is proportional to the difference between the temperature of the coffee and the room temperature. Use this information to write a differential equation describing the derivative of the coffee temperature in terms of T and t. Use C as your proportionality constant. C should be a positive number. Write T instead of T(t).
Let R be the rate at which the coffee cools down. Since R is proportional to the difference between the temperature of the coffee, T and the room temperature, we write
R = C(T - 18)
Where C is the proportionality constant.
To write a differential equation describing the derivative of the coffee temperature in terms of T and t, we need to differentiate
