Hey all. On Wiki (http://en.wikipedia.org/wiki/Fourier_transform#Properties_of_the_Fourier_transform) they have some really good pictures explaining the Fourier transform - see the introduction section. The Fourier transform is of an exponentially decaying sinusoid - where the sinusoid (cosine) has a frequency of 3Hz. I do not understand why the Fourier transform has "magnitude" for frequencies surrounding 3Hz? Isn't 3Hz the only frequency present in the function? Thanks. Nick.