this is for my stats class and i dont have a calc book with me...

the sum of 1/(3^x) where x is from 1 to infinity

thanks

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- Sep 23rd 2008, 02:45 PMDubulussum of infinite series
this is for my stats class and i dont have a calc book with me...

the sum of 1/(3^x) where x is from 1 to infinity

thanks - Sep 23rd 2008, 02:53 PMPlato
$\displaystyle \frac{a}

{{1 - r}} = \frac{{\frac{1}

{3}}}

{{1 - \frac{1}

{3}}}$ - Sep 23rd 2008, 03:09 PMDubulus
what do a and r represent, and why are they both 1/3 in this case? thanks

- Sep 23rd 2008, 03:17 PMicemanfan
a is the first term of the series, and r is the common ratio (the ratio between consecutive terms).

- Sep 23rd 2008, 03:20 PM11rdc11
This is a geometric series so you use the formula plato gave to find the sum

- Sep 23rd 2008, 03:29 PMDubulus
ok what if the ratio is 5x/6, is there another formula i can use?

this is for solving the sum of:

x * (1/6) * (5/6)^(x-1)

where x is 1 to infinity - Sep 23rd 2008, 03:32 PMPlato
$\displaystyle \sum\limits_{k = J}^\infty {ax^k } = \frac{{ax^J }}

{{1 - x}},\,\,\left| x \right| < 1$ - Sep 23rd 2008, 03:34 PMDubulus
- Sep 23rd 2008, 03:45 PMPlato
- Sep 23rd 2008, 03:53 PMicemanfan
- Sep 23rd 2008, 04:46 PMDubulus