Small side note, don't forget to escape your trig functions in TeX! Else it will render your "cos" in italitcs (product of variables c, o and s) as in this arti

Small side note, don't forget to escape your trig functions in TeX! Else it will render your "cos" in italitcs (product of variables c, o and s) as in this article, and thousands of others; the only thing more surprising than people not noticing this is TeX not giving a warning about it.