配方=arlx*+2x,Za'aym +(2aan-ar,x,)"l法0-a(ala,)+Zaxx,=228=an[x+(2a'ayx,)P-a(2a,)+2axx,j=2-=anlx +(Za'y)P+≥22bx;j=2i=2 j=22b*,=-a(24,)~+22agx,x这里，i=2 j=2i=2i-2 j-2是一个X2,X3,,x的n一1元二次型85.2标准形§5.2 标准形 这里， 2 1 11 1 1 11 1 2 11 2 1 1 2 [ 2 ( ] ) n j j j n j j j a x x a a x a a x − = − = = + +   1 2 1 2 11 1 11 1 11 1 2 2 2 2 [ ( )] ( ) n n n n j j j j ij i j j j i j a x a a x a a x a x x − − = = = = = + − +    1 2 11 1 2 1 1 2 2 ( ) n n n ij i j i j j j j a x a a a x x − = = = −  + 1 2 11 1 11 1 2 2 2 [ ( )] n n n j j ij i j j i j a x a a x b x x − = = = = + +   1 2 11 1 2 2 2 2 2 ( ) n n n n n ij i j j j ij i j i j j i j b x x a a x a x x − = = = = =    = − + 是一个. 2 3 的n－1元二次型. , , , n x x x 配方 法