matlab有限元法解结构频率

syms n E I l w a

n=2

A=[24-312*a 12*l-44*l*a;6*l-22*l*a (4+6*n)*l^2-5*l^2*a] det(A) %得到592*a^2*l^2-4584*a*l^2 + 312*l^2

solve('592*a^2*l^2 - 4584*a*l^2 + 312*l^2=0','a')

得到：

a1=(7*6465^(1/2))/148+ 573/148

a2=573/148 - (7*6465^(1/2))/148

(420*8/11)^0.5

(420/((7*6465^(1/2))/148 + 573/148))^0.5 ( 420/( 573/148 - (7*6465^(1/2))/148))^0.5