As I understand, you want to compute the numerical solution to a certain differential equation in MATLAB, using the ode45 or another appropriate function.
The differential equation in question here is a Delay-Differential Equation . I assume, from the A(t-1) term in the first equation, that A is a function of the independent variable t, A(t) . This would mean that there is a delay introduced when attempting to compute the derivative of this function and hence it cannot be solved using Ordinary Differential Equation solvers like ode45.
MATLAB contains different solvers for differential equations with delay, such as dde23 , ddesd and ddensd . You can find more about these functions in the following reference :
I believe that the example of “Neutral DDE with Two Delays” given on the page below (for the ddensd solver) will help you set up the code for the differential equation described in the question.