clear;clc; %digital resolution is 1000 resolution=1000; i=1:resolution; j=(2*pi)/resolution; %The first function amplitude=16; frequency=2; y1=amplitude*cos(frequency*i*j); %The second function amplitude=6; frequency=14; y2=amplitude*sin(frequency*i*j); y=y1+y2; plot(y) FFTy=fft(y)'; figure(1) dy1=diff(y)*resolution; plot(dy1) ylabel('velocity') figure(2) dy2=diff(dy1)*resolution; plot(dy2) ylabel('acceleration')