西安毛子科技大学XIDIAN UNIVERSITYX1X2..=其中xi为x,的共轭复数，..Xn又由A实对称，有 A=A，A=A，A=A.. =() =(A) =(FA)5(E A') =(AE) =(AE)=(5) =() =§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  =