41S=其中 xi为x,的共轭复数，Xn又由A实对称，有 A=A，A'=A，A=A:. F=E() =E(AS) =(A)5-(F A)5 =(AE)5 =(AE)5=() =() =S9.6对称矩阵的标准形K§9.6 对称矩阵的标准形A A A A = = , ,  其中 x x i 为 i 的共轭复数， 1 2 , n x x x      =         令    0   ( )   A  =  = ( ) A  又由A实对称，有 ( )    0 =  A A   =   ( ) A     ( ) 0 =  = ( )   A  = = ( ) A  0 = ( )       0  =