The value of the investment at the time t + ∆t is then given by \label{eq:1}S(t+\Delta t)=S(t)+(r\Delta t)S(t)+k\Delta t, where at the end of the time interval ∆t, r\Delta tS(t) is the...The value of the investment at the time t + ∆t is then given by \label{eq:1}S(t+\Delta t)=S(t)+(r\Delta t)S(t)+k\Delta t, where at the end of the time interval ∆t, r\Delta tS(t) is the amount of interest credited and k∆t is the amount of money deposited (k > 0) or withdrawn (k < 0).
