Apologies for the off-topic question; as usual I'm trying to draw upon the unparalleled knowledge and sagacity of the r-help list. Please reply off-list if you can help me out.
A collaborator of mine found a formula we need, on sheets which he had photocopied out of a book, some years ago. He cannot remember which book (he's getting to be as senile and forgetful as I am, poor bloke!). He thinks it was (and it appears to have been) a large encylopedic tome devoted to extensive tables of formulae, integrals and series, and stuff like that. The formula in question is oo 1 1 1 SUM --- cos(k*x) = --- ln (----------------) 0 < x < 2*pi . k=1 k 2 2*(1 - cos(x)) (I.e. the right hand side is a function whose Fourier coefficients are 1/k, k > 0). Note that ``oo'' is my attempt to render the infinity symbol in ASCII. Does anyone know of a source where this formula may found/cited? (It doesn't *have* to be the same source from which my collaborator originally copied it!) It must be well-known/in lots of books, mustn't it? Said he, hopefully. Thanks for any assistance. cheers, Rolf Turner [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html