But \(\mu_{ij}\) is defined to be the derivative of \(p_{ij}(t)\) evaluated at t=0. And in time homogeneous case, for it does not depend upon 't' so derivative of \(p_{ij}(t)\) should equal.
I understand the example you gave, but I am not able to understand this concept which I mentioned above.
And also in the second point you mentioned that derivative of pij(t) is the rate of change over t years, but if we are differentiating a function then we should get the rate of change in that instance or in a very small amount of time.
Last edited by a moderator: Apr 9, 2014