Might be simple, but i don't get it. Why is the integral in the last line approximately equal to $n(\varphi(\frac{-1}{2n}) - \varphi(\frac{1}{2n}))$?
Approximating an integral
-1
$\begingroup$
analysis
distribution-theory
-
0Please mention [the name of the book](http://books.google.com/books?hl=en&id=T7vEOGGDCh4C&pg=PA17) the next time you ask about something you see in a book... – 2012-07-16
-
0it is taken from Robert Stichartz, A Guide to Distribution Theory and Fourier Transforms, page 17. – 2012-07-16