dS dt
=1000r 100 e(r/100)
The rate of change of the value of an investment, S, with respect to time, t ≥ 0, is given by
where r is the annual interest rate (assumed constant) and the principal of the investment is S(0) = 1 000
1.(a) Find an expression for S(t), that is, the value of the investment at time t.