clear;
eta=0:0.01:3;
zeta=[0.1,0.25,0.5,1];
hold('on');
for n=1:length(zeta)
    mf=1./sqrt((1-eta.^2).^2+(2*zeta(n)*eta).^2);
    plot(eta,mf);
end
xlabel('f/fn');ylabel('x/xst');grid('on');
