finding harmonic amplitudes of a sinewave

I have a sine wave with frequency of 'wn', how can I get the amplitudes of its harmonics i.e amplitude at '2*wn', '3*wn' ... I tried using 'fft' function in matlab, if fft does that then why the sumation of all harmonics from 'fft' does not equal to the max amplitude of actual signal?

Answer 1

[Xavier]

Hopefully this will work for you

https://uk.mathworks.com/matlabcentral/answers/306048-obtaining-amplitude-values-from-an-fft#answer_237757