Hi, I am new in this group. I am trying to apply fft on my data but it seems there is something that I don't understand. I searched previus posts but nothing helped me. Can anyboby help me to apply fft on this function, f(x) = sin(2*x) + sin(3*x) + sin(4*x) , x in [0 , b] b = 100 , 200 , 300 I have serious problems with the frequency domain as well as the amplitude of the transformed signal. Thanks a lot and please excuse my english.