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 vectorif rt<ct   t=t';endw=2*pi*f;one=ones(length(t),1);%Breaks 3.81 into two partsRs1=one./(w*t);Rs2=sqrt(2*(1-cos(w*t)));%Calculates 3.81Rs=one+Rs1.*Rs2;aa=version;ll=length(aa);plot(t,Rs)grid ontitle(['Response spectrum of a SDOF system with f = ',num2str(f),' Hz']);ylabel('Dimensionless maximum response - (xk/Fo)max')xlabel('Rise time (t_1)')