Missing terms of a geometric seqeunce

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    Geometric Terms
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The discussion revolves around finding the missing terms in a geometric sequence starting with 3 and including the term 32x+1. The formula for the nth term of a geometric sequence, tn = ar^(n-1), is applied to derive the common ratio. The user simplifies the expression 32x+1 / 3 to find the common ratio, concluding that it equals 3x after further simplification. The conversation emphasizes the importance of simplifying expressions before taking square roots in geometric sequences. Ultimately, the user successfully identifies the missing terms with the help of hints provided.
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Homework Statement


Write the first 5 terms of the geometric sequence
3, __ , 32x+1, __, __

Homework Equations


tn=arn-1


The Attempt at a Solution


tn=arn-1
32x+1=3r3-1
r2=32x+1 / 3
r=√32x+1 / √3

I'm stuck
 
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Before taking the square root, try to simplyfy the right side. What is \frac{3^{2x+1}}{3^{1}}?
 
Hint:

If a,b,c are three consecutive terms of a geometric sequence, b^2 = ac.
 
Villyer said:
Before taking the square root, try to simplyfy the right side. What is \frac{3^{2x+1}}{3^{1}}?

Ohh I see. 32x+1 / 31 = 32x. And the square root of that is 3x.
Thank you
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Essentially I just have this problem that I'm stuck on, on a sheet about complex numbers: Show that, for ##|r|<1,## $$1+r\cos(x)+r^2\cos(2x)+r^3\cos(3x)...=\frac{1-r\cos(x)}{1-2r\cos(x)+r^2}$$ My first thought was to express it as a geometric series, where the real part of the sum of the series would be the series you see above: $$1+re^{ix}+r^2e^{2ix}+r^3e^{3ix}...$$ The sum of this series is just: $$\frac{(re^{ix})^n-1}{re^{ix} - 1}$$ I'm having some trouble trying to figure out what to...
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