下列二次型中,属于正定型的是()
A.f(x1,x2,x3)=x21+x22 B.f(x1,x2,x3)=x21+x22+2x1x2+x23 C.f(x1,x2,x3)=4x21+3x22+6x23-x1x2-x1x3 D.f(x1,x2,x3)=x21+x22+x23+2x1x2+2x1x3+2x2x3正确答案C
下列二次型中,属于正定型的是()
A.f(x1,x2,x3)=x21+x22 B.f(x1,x2,x3)=x21+x22+2x1x2+x23 C.f(x1,x2,x3)=4x21+3x22+6x23-x1x2-x1x3 D.f(x1,x2,x3)=x21+x22+x23+2x1x2+2x1x3+2x2x3正确答案C