Consider the function $$f(t) = 2 \sin(t)+\sin(2t)+25 \sin(400t)$$ (for example).
In this case, how many samples of this function would I have to take, and at what sampling frequency, to determine the three frequencies it is composed of? And, how exactly would I identify those frequencies from the Fourier coefficients?
This is not a homework problem by the way, just something that I'm confused about. Please help!