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What is the solution to ΣΣ(sinx)(cosx)?

  1. Dec 4, 2007 #1
    what is the solution to this ?
  2. jcsd
  3. Dec 4, 2007 #2
    Your question isn't clear. What variables are you summing over? And where do those appear in the summand?
  4. Dec 6, 2007 #3
    Are one of the trig functions supposed to be a function of y?
  5. Dec 6, 2007 #4


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    Since there was no y mentioned in the entire post, apparently not! But Xevarion's point is more than that. Typically "x" (or "y") in a function represents a continuous variable- but the sums must be over discrete indicies.

    Perhaps it was
    [tex]\sum_{n= 0}^\infty \sum_{m= 0}^\infty sin(n)cos(m)[/tex]
    that was intended. But the only way we will know for sure is if abhaaiitg tells us!
  6. Dec 7, 2007 #5
    yeah it was as u think
  7. Dec 7, 2007 #6
    That sum doesn't converge. There are arbitrarily large $m, n$ with $|\sin(n)\sin(m)|$ close to 1.
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