save this function with the name dif_eq
function da=dif_eq(x,a,tim,f)
f1=interp1(tim,f,x)
da=(f1-a)/x;
then call the function:
t=[0.1:10]; % time vector
x0=0; % initial condition
f=rand(1,numel(t)); % your vector f, same length as vector time t
[X,A]=ode45(@(x,a) dif_eq(x,a,t,f),t,x0);
plot(X,A)
