SOLUTION: If the sum of the geometric sequence 2,6,18,54,162,... is 19682. In what terms are added to be needed?

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Question 1087685: If the sum of the geometric sequence 2,6,18,54,162,... is 19682. In what terms are added to be needed?
Answer by ikleyn(52817) About Me  (Show Source):
You can put this solution on YOUR website!
.
%282%2A%283%5En-1%29%29%2F%283-1%29 = 19682  ====>  3%5En-1 = 19682  ====>  3%5En = 19683  ====>  n = log%283%2C%2819683%29%29 = 9.

Answer. 9 term sum.


For introductory lessons on geometric progressions, see the lessons
    - Geometric progressions
    - The proofs of the formulas for geometric progressions
    - Problems on geometric progressions
    - Word problems on geometric progressions
in this site.


Also,  you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Geometric progressions".