quadratic(x1,x2,x3)=2(a1x1+a2x2+a3x12,333)2+(b1x1+b2x2+b3x3)2b a=a2=b2 Remember3 b3 (1) prove that the matrix corresponding to quadratic f is 2aaT+BBT; (2)If and B are orthogonal and both are unit vectors, it is proved that the standard form of F under orthogonal transformation is 2yi +.