Question 4: 20 Marks In one theory of learning, the rate at which a course is memorized is assumed to be proportional to the product of the amount already memorized and the amount that is still left to be memorized. Assume that
Qdenotes the total amount of content that has to be memorized, and
I(t)the amount that has been memorized after
thours. (4.1) Write down a differential equation for
l, using
kfor the constant of proportionality. Also, write down the initial value
I_(0). (4.2) Draw the phase line of the model. (4.3) Use the phase line to sketch solution curves when the initial values are
I_(0)=Q,I_(0)=(Q)/(2), and
I_(0)=0.
