function VTB2_3(z,rmin,rmax)

%VTB2_3 Steady state magnitude and phase of a single degree of freedom 
% damped system.  
% VTB2_3(zeta,rmin,rmax) plots the response of a single degree of 
% freedom system with damping ratio zeta between the frequency 
% ratios rmin and rmax.



r=rmin:(rmax-rmin)/1000:rmax;

A0=(1)./sqrt((1-r.^2).^2+(2*z*r).^2);%(2.30)

phi=atan2(2*z*r,1-r.^2);%(2.30)

semilogy(r,A0)

xlabel('Frequency Ratio')

ylabel('Normalized Amplitude')

title('Normalized Amplitude versus Frequency Ratio')

text(0,0,'Press Return To Continue','sc')

pause

plot(r,phi)

xlabel('Frequency Ratio')

ylabel('Phase')

title('Phase versus Frequency Ratio')

text(0,0,'Press Return To Continue','sc')