calculate the sum of the first 50 terms.

1+9+17+ ...

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- Jan 12th 2012, 07:38 PMahmedbarithmetic series
calculate the sum of the first 50 terms.

1+9+17+ ... - Jan 12th 2012, 07:44 PMpickslidesRe: arithmetic series
Use $\displaystyle S_n = \frac{n}{2}(2a+(n-1)d)$

n=50 so,

$\displaystyle S_{50} = \frac{50}{2}(2a+(50-1)d)$

now all you need is 'a' the first term and 'd' the common difference from the series, what do you get? - Jan 12th 2012, 07:49 PMahmedbRe: arithmetic series
thanks.

and whats the geometric series forumla??? - Jan 12th 2012, 07:51 PMpickslidesRe: arithmetic series
Read this fella

Geometric series - Wikipedia, the free encyclopedia - Jan 13th 2012, 04:04 AMahmedbRe: arithmetic series
what does the r represent?

- Jan 13th 2012, 11:08 AMskeeterRe: arithmetic series