show that

where K is a rational constant to be found

so I just plug in numbers for 'r' e.g. r=1,2,3 , n and get the sequence 2, 5/2 , 3 ,.....

but not sure how to prove it equals the expression

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- May 29th 2009, 12:05 PMTweetyseries, sum help
show that

where K is a rational constant to be found

so I just plug in numbers for 'r' e.g. r=1,2,3 , n and get the sequence 2, 5/2 , 3 ,.....

but not sure how to prove it equals the expression - May 29th 2009, 12:19 PMMoo
Hello !

The sum can be rewritten this way :

The first one is known :

And (you add n times 1)

So the sum is (Nod) - May 29th 2009, 12:20 PMPlato

- May 29th 2009, 02:50 PMTweety
- May 29th 2009, 02:59 PMPlato
This is one of the best known and widely used sums: .

If you**add J to itself N times**you get NJ so: .

There are several of these special sums that you need to learn. - May 29th 2009, 03:16 PMTweety
- May 30th 2009, 07:25 AMHallsofIvy
Yes, of course you can. But your original post gave no clue that you

**knew**that formula so responders were telling you how to do it without that formula. In fact, that formula is derived by just the method they describe.