Question

The sum to infinity of a convergent is series is 243.The sum of the first five terms 242.Determine the values of the common ratio and the first term

Answer 1

just use your GP sum formula. You have

a/(1-r) = 243
a (1-r^5)/(1-r) = 242
Now divide and you have
1-r^5 = 242/243 = 1 - 1/243

. . .

Answer 2

Thanks sir