Continuity and discontinuity in fourier series?

Can somebody please explain continuity and discontinuity in fourier series?

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This seems very broad, and it would be very difficult to guess where to start answering your question. Could you please elaborate, and indicate particular aspects of the theory you are having trouble with? – Jonas Meyer Nov 13 '10 at 19:38
If you mean a discontinuity like the square wave you can look at this picture problemasteoremas.files.wordpress.com/2008/05/ondaquadrada.gif – Américo Tavares Nov 13 '10 at 19:45