Supposerandsare positive integers with no common factor and

1 - 1/2 + 1/3 - 1/4 + ... + 1/1339 - 1/1340 = r/s

Find a prime factor of r.

Have no idea how to solve this so please help.

Please explain it step by step clearly. Thanks.

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- January 9th 2013, 11:47 PMspritermanGeometric Series challenging question
Suppose

*r*and*s*are positive integers with no common factor and

1 - 1/2 + 1/3 - 1/4 + ... + 1/1339 - 1/1340 = r/s

Find a prime factor of r.

Have no idea how to solve this so please help.

Please explain it step by step clearly. Thanks. - January 10th 2013, 04:35 PMspritermanRe: Geometric Series challenging question
So no one knows how to answer this?

- January 10th 2013, 04:53 PMPlatoRe: Geometric Series challenging question
Oh no, many of us know what needs to be done.

But why do you think we should do your work for you?

Here it is.

Now what can you do with that? - January 10th 2013, 05:09 PMspritermanRe: Geometric Series challenging question
Doesn't that equation make the 1 negative? The starting term of the series is a positive.

- January 10th 2013, 06:20 PMPlatoRe: Geometric Series challenging question
- January 11th 2013, 04:25 PMspritermanRe: Geometric Series challenging question
- January 12th 2013, 06:19 PMProve ItRe: Geometric Series challenging question
Also, this is not a geometric series...