例1设 f(x,x2,x3,x)=2x2+x1x2+2x1x3+ +4x2x4+x2+512 则它的矩阵为 0 002 1010 0205 8 2021/2/202021/2/20 8 例1 设 2 1 2 3 4 1 1 2 1 3 2 2 2 4 3 4 ( , , , ) 2 2 4 5 f x x x x x x x x x x x x x = + + + + + + 1 2 1 0 2 1 0 0 2 2 1 0 1 0 0 2 0 5 A         =           则它的矩阵为