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Re: Help with finding zeros
Posted:
Sep 13, 2010 11:37 AM


On Sep 13, 10:01 am, "Rod" <rodrodrod...@hotmail.com> wrote: > "Greg Neill" <gneil...@MOVEsympatico.ca> wrote in message > > news:BUpjo.55715$iw4.28826@unlimited.newshosting.com... > > > > > > > Robert Adams wrote: > >> I could use a little help trying to solve the following engineering > >> problem (no, I am not a student looking for homework help!) > > >> I need to find the values of w which cause the following summation to > >> go to zero > > >> sum (n = 1 to N) of exp(i*w*ln(n)) > > >> where i is the usual sqrt(1) > > >> For a given N, there are infintely many solutions due to the > >> periodicity of exp(i ...) > >> How do I find these solutions? > > >> Thanks for any pointers. > > >> Bob Adams > > > Have you looked into expanding the exponentials into > > trig form? You'll then have a sum of cos and > > imaginary sin terms which will each have to sum to > > zero separately. > > That's my approach as well > Wouldn't w have to be complex to achieve both series being zero. > > Is this not a truncated zeta function? Hide quoted text  > >  Show quoted text 
Yes, this is related to the zeta function.
I was hoping to to find a solution where w is real, but this may not be possible as you point out
Bob



