Answer:
The required equation would be
Where, k is constant of proportionality.
Explanation:
Differential equation : is an equation that contains one or more functions and their derivatives.
Where, derivatives shows the rate of change of a variable with respect to other variable.
Given,
Change in temperature T of coffee with respect to t ( time ) is proportional to difference between the fixed temperature M and temperature of coffee,
i.e.
( if M > T, Change is M - T if M < T then change is T - M)
Where,
k = constant of proportionality.