# Geometric Sequence help!

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#1
Does anyone know how to do this question? Any help will be greatly appreciated

The sum of the first two terms of a geometric series is 1 and the sum its first four terms is 5. If all of its terms are positive, find the first term and the common ratio.
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1 month ago
#2
(Original post by Celina Davis)
Does anyone know how to do this question? Any help will be greatly appreciated

The sum of the first two terms of a geometric series is 1 and the sum its first four terms is 5. If all of its terms are positive, find the first term and the common ratio.
Let be the first term, and be the common ratio.

Then and .

Note that the second one can be rewritten as
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