Revision as of 10:18, 20 January 2011 by Mboutin (Talk | contribs)


In question 2e

$ x(t)= \sum_{k=-\infty}^\infty \frac{1}{1+(x-7k)^2} \ $

should it be like this?

$ x(t)= \sum_{k=-\infty}^\infty \frac{1}{1+(t-7k)^2} \ $ 

yes, it should be. The correction has been made. -pm

and I was trying to find out what the peak value is for this question but turns out to be very hard to calculate the sum

$ \sum_{t=-\infty}^\infty \frac{1}{1+t^2} \ $            and wolfram said answer is π * coth(π). is there any easier way to do that?

You do not have to evaluate the sum. In particular, you do not need the peak value of that functions. Try to guess the period directly by looking at the sum. If you have no idea how to do this, read this page first. -pm

Yimin. Jan 20


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