How Do You Solve a Geometric Progression with Sum and Term Constraints?

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Homework Help Overview

The discussion revolves around an infinite geometric progression with constraints on the sum of the first two terms and the value of the third term. The original poster presents a problem involving the first term and the common ratio of the progression.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants express confusion about the problem setup and seek clarification on how to approach it. Some participants note the equations derived from the given conditions, while others indicate a lack of understanding of the initial steps required to solve the problem.

Discussion Status

The discussion is ongoing, with some participants attempting to outline the relationships between the terms of the geometric progression. There is a recognition of the need for further exploration of the equations provided, but no consensus has been reached on the next steps.

Contextual Notes

Participants mention the challenge of starting the problem and express a desire for guidance without receiving direct answers. There is an emphasis on understanding the equations related to the geometric progression.

jinx007
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An infinite geometric progression has a finite sum. Given that the sum of the first two terms is 9 and the third term is 12.

1/ Find the value of the first term and the common ration r.
 
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Work shown?
 
thrill3rnit3 said:
Work shown?

what? i cannot really understand what you r saying
i just need help..lolzz...in fact don't really know where to start..y the way i know the equation
 
jinx007 said:
what? i cannot really understand what you r saying
i just need help..lolzz...in fact don't really know where to start..y the way i know the equation

Well, I can't just spoonfeed you with the answer.

A geometric progression can be written as a, ar, ar2, ar3,..., arn

Where a is the first term, and r is the common ratio

If the sum of the first two terms is 9, we can rewrite that as

a + ar = 9

If the third term is 12, we can rewrite it as

ar2 = 12

Now you have 2 equations in 2 unknowns. I think it should be solvable now.
 

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