13.-|||-多项式 ((x)_(1),(x)_(2),(x)_(3))=(({x)_(1)+(x)_(2))}^2+(({x)_(1)+(x)_(3))}^2-4(({x)_(2)-(x)_(3))}^2 的标准形为() ()-|||-A .({y)_(1)}^2+({y)_(2)}^2-|||-B .({y)_(1)}^2-({y)_(2)}^2-|||-C .({y)_(1)}^2+({y)_(2)}^2-4({y)_(3)}^2-|||-D .({y)_(1)}^2+({y)_(2)}^2-({y)_(3)}^2

二次型((x)_(1),(x)_(2),(x)_(3))=(({x)_(1)-(x)_(2))}^2+(({x)_(2)-(x)_(3))}^2+(({x)_(

22.-|||-设二次型 ((x)_(1)(x)_(2),(x)_(3))=({x)_(1)}^2+({x)_(2)}^2+({x)_(3)}^2+2a(x)_

21.设二次型((x)_(1),(x)_(2),(x)_(3))=(a)_(1)({x)_(1)}^2+(a)_({x)_(2)}^2+(a-1)({x)_(3

) (x)_(1)+4(x)_(2)-2(x)_(3)+8(x)_(4)=2 -(x)_(1)+2(x)_(2)+3(x)_(3)+4(x)_(4)=1 (x)

1.已知方程组 ) (x)_(1)+(x)_(2)+(x)_(3)+(x)_(4)=2 3(x)_(1)+2(x)_(2)+(x)_(3)+(x)_(4)=a

已知函数(x)=2(x)^3+(x)^2+2x-1定义在区间[-1,1]上,在空间(x)=2(x)^3+(x)^2+2x-1上求函数(x)=2(x)^3+(x)

用最速下降法求解(x)=({x)_(1)}^2+2(x)_(1)(x)_(2)+2({x)_(2)}^2-4(x)_(1)-3(x)_(2),取(x)=({x)

若多项式(x)=(x)^4+(x)^3-3(x)^2-4x-1 和 (x)=(x)^3+(x)^2-x-1，则f(x)和g(x)的公因式为（）。A、x+1B、x

已知二次型((x)_(1),(x)_(2),(x)_(3))=({x)_(1)}^2+a({x)_(2)}^2+({x)_(3)}^2+2b(x)_(1)(x)

线性方程组 ) (x)_(1)+2(x)_(2)-2(x)_(3)=1 2(x)_(1)+4(x)_(2)-4(x)_(3)=2 3(x)_(1)+6(x)_