function vtb6% VTB6%% VTB6_1 Natural frequencies and mode shapes of a uniform bar.% VTB6_2 Torsional natural frequencies and mode shapes of a %        uniform bar.% VTB6_3 Natural frequencies and mode shapes for an Euler-Bernoulli%        beam with a given boundary conditon.% VTB6_4 Comparison of natural frequencies for an Euler-Bernoulli%        beam, a beam including rotary inertia, and a beam including %        shear deformation.