FORM by J.Vermaseren,version 3.3(Jun 10 2009) Run at: Wed Apr 17 07:20:58 2013 * PHZ 3113 Weber & Arfken, p.219: * 3x3 determinant for normal modes. * kM=k/M, km=k/m, la=omega^2 eigenvalues wanted. Symbols kM,km,la; Off stat; Local det=(kM-la)*(2*km-la)*(kM-la)+0+0 -(kM-la)*(-km)*(-kM) -(-kM)*(-km)*(kM-la)-0; * Reduction by eigenvalue 1: la=0. Local dla=-det/la; * Remaining eigenvalues la2,3=km+kM-/+Sqrt[(km+kM)^2-2*kM*km-kM^2]. * Sqrt=-/+km: la2=kM, la3=kM+2*km. Check: Local Zero=dla-(la-kM)*(la-kM-2*km); Bracket la; Print; .sort det = + la * ( - 2*kM*km - kM^2 ) + la^2 * ( 2*km + 2*kM ) + la^3 * ( - 1 ); dla = + la * ( - 2*km - 2*kM ) + la^2 * ( 1 ) + 2*kM*km + kM^2; Zero = 0; .end 0.00 sec out of 0.00 sec