Compute 1 + \frac{3}{5} + \frac{5}{5^2} + \frac{7}{5^3}.
1 + (sumfor(n, 1, 1000000, (5^ -n)*(1 + 2*n)))==converges to 15/8 ==1 + 7/8
Answered a few days ago, here.
web2.0calc.com/questions/arithmetic-geometric-series#r3
