function vtb5_3(mu,beta)
%VTB5_3 Normalized magnitude of the primary mass for absorber design.
% VTB5_3(mu,beta) plots the normalized magnitude of the primary mass
% for a vibration absorber design.  The variable mu is defined
% as the absorber mass divided by the primary mass (ma/m).  The 
% ratio of natural frequencies (wa/wp) is defined as beta.
 
%beta=1;
wdr=0:.01:2;          %normalized frequency wdr/wa
wdr=wdr';
one=ones(length(wdr),1);

num=one-wdr.^2;

den1=(one+mu*beta^2*one-wdr.^2);
den2=(one-wdr.^2);
den=den1.*den2-mu*beta^2*one;

f=num./den;

mb=mu*beta^2;
eqn=[1 0 -(4+2*mb) 0 (1+(2+mb)^2) 0 -(2+2*mb)];
r=sort(roots(eqn));       %Solves for crossings of 1
r1=r(4);
r2=r(5);
j=[0 1];
axis([0 2 0 3]);
plot(wdr,abs(f),wdr,one,[r1 r1],j,'--',[r2 r2],j,'--')
axis;
hold

%Draws shaded lines
sh=r1:.1*(r2-r1):r2;
for i=1:length(sh)
   plot([sh(i) sh(i)],j,'--')
end
tmp1='Normalized magnitude of primary mass for mu = ';
title([tmp1,num2str(mu),' and beta = ',num2str(beta)])
ylabel('|Xk/Fo|')
xlabel('normalized frequency wdr/wa')
text(.1,.8,'Useful operating range','sc')
text(.1,.75,[num2str(r1),' < wdr/wa < ',num2str(r2)],'sc')
hold