[20] An investment provides an infinite series of annual payments of d, c, ..., first payment one year from now, where d is the effective rate of discount. In lieu of these payments, a single payment equal to their sum is to be made at time t. Show that using the method of equated time, t where i is the equivalent annual effective interest rate and 8 is the equivalent force of interest. (hint: d+ + + ... = In(1 d).) si [20] An investment provides an infinite series of annual payments of d, c, ..., first payment one year from now, where d is the effective rate of discount. In lieu of these payments, a single payment equal to their sum is to be made at time t. Show that using the method of equated time, t where i is the equivalent annual effective interest rate and 8 is the equivalent force of interest. (hint: d+ + + ... = In(1 d).) si