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The sum of a sequence (Posted on 2004-12-14) Difficulty: 4 of 5
Find the sum of the sequence: x, 2x2, 3x3, 4x4, 5x5, ... , nxn.

See The Solution Submitted by Mohammad    
Rating: 3.4286 (7 votes)

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answer Comment 10 of 10 |

The required sum is A(x,n)*(1-x)^(-2), where:

A(x,n) = n*(x^n)(x-1) - (x^n - 1)

Edited on February 18, 2008, 2:53 pm
  Posted by K Sengupta on 2008-02-18 14:50:49

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