则 f(α,β)= (Ex;e,Ey,6,)=Zf(6,8,)x,x,l i=l2A=令 a, = f(8,,8,),i, j =1,2,..",n,anly1则 (α,β)=(xi x2 .. xn)ASf(e1,e)) ... f(e1,en)其中A:f(en,e)) ... f(en,en)$10.3双线性函数A§10.3 双线性函数 则 1 1 ( , ) ( , ) ( , ) , n n i i i i i j i j i j f f x y f x x       = = = =    11 1 1 n n nn a a A a a   =       ( , ), , 1,2, , , ij i j 令 a f i j n = =   ( ) 1 2 1 2 ( , ) , n n y y f x x x A y       =       1 1 1 1 ( , ) ( , ) . ( , ) ( , ) n n n n f f A f f           =       则 其中