Find all values of x in which the series converges

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SUMMARY

The series Ʃ (4x+5)^n/2^n converges for values of x within the interval (-7/4, -3/4). The convergence is determined using the ratio test, which states that a series converges if the limit of the ratio of successive terms approaches zero. The correct answer was confirmed by multiple participants in the discussion, affirming the interval as the solution.

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Homework Statement


Find all values of x for which the series Ʃ (4x+5)^n/2^n converges. (n=0; n→∞)
Answer choices: (3/4,-3/4)
(3/4,7/4)
(-7/4,7/4)
(-5/4,5/4)
(-7/4,-3/4)



Homework Equations






The Attempt at a Solution


I think the answer is -7/4,-3/4. If I remember correctly, there is a test that states that a series converges if the limit goes to 0. Is this correct?
 
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hi turbokaz! :smile:

(yes, correct answer)

look at it this way …

it's ∑ an where a = (4x+5)/2

so what is the equation for when ∑ an converges? :wink:
 

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