function vtb5_6(mu,rmin,rmax)
%VTB5_6 Surface plot of the normalized amplitude of the primary
%mass for a damped absorber design.
%  VTB5_6(mu,rmin,rmax) displays the 3-D plot for normalized
%  amplitude for a given value of mu.  The function is plotted
%  between the normalized frequencies rmin and rmax, with the
%  damping ratio ranging from 0 to 1.

r=rmin:(rmax-rmin)/20:rmax;

z=.05:.025:1;

[r,z]=meshdom(r,z);

num=4*z.^2+r.^2;
den1=4*z.^2 .*(r.^2+mu*r.^2-1).^2;
den2=((r.^2-1).^2).*r.^2;
f=sqrt(num./(den1+den2));  %equation 5.42

mesh(f)
ropt=sqrt(2/(2+mu));
zopt=1/sqrt(2*(mu+1)*(mu+2));

text(.10,.85,['The optimal frequency ratio = ',num2str(ropt)],'sc')
text(.10,.80,['The optimal damping ratio = ',num2str(zopt)],'sc')

text(.48,.17,num2str(rmin),'sc')
text(.92,.31,num2str(rmax),'sc')
text(.43,.17,'0','sc')
text(.06,.39,'1','sc')
text(.60,.23,'normalized frequency - r','sc')
text(.15,.23,'damping ratio - zeta','sc')

title('Normalized magnitude of the primary mass')