InterviewSolution
Saved Bookmarks
| 1. |
The sum of first two terms of an infinite G.P. is 5 and each term isthree times the sum of the succeeding terms. Find the G.P. |
|
Answer» Let the G.P. is `a, ar,ar^2...oo` Here, `a` is the first term and `r` is the common ratio. Then, `a+ar = 5` Also, `T_n = 3(T_(n+1)+T_(n+2)+...oo)` `=>ar^(n-1) = 3(ar^n+ar^(n+1)+...oo)` `=>ar^(n-1) =3ar^n(1+r+r^2...oo)` `=>1 = 3r(1/(1-r))` `=>1-r = 3r` `=>4r = 1` `=> r = 1/4` `:. a +a(1/4) = 5` `=>5/4a = 5` `=> a= 4` So, G.P. is `4,1,1/4,1/16...oo.` |
|