function vtb3_4(f)

%VTB3_4 Response spectrum for a SDOF system.
% VTB3_4(f) will display the response spectrum to a partial ramp 
% input(see Figure 3.13) for the system with natural frequency 
% f (in Hz). 


t=linspace(.001*4/f,10/f,200);

size(t)



[rt,ct]=size(t);

%Checks to make sure t is a column vector

if rt<ct

   t=t';

end



w=2*pi*f;



one=ones(length(t),1);



%Breaks 3.81 into two parts

Rs1=one./(w*t);

Rs2=sqrt(2*(1-cos(w*t)));



%Calculates 3.81

Rs=one+Rs1.*Rs2;



plot(t,Rs)

title(['Response spectrum of a SDOF system with f = ',num2str(f),' Hz']);

ylabel('Dimensionless maximum response - (xk/Fo)max')

xlabel('Rise time (t1)')