Question

已知x+y+z=0,x^2 + y^2 + z^2 = 1 ,试求下列各式的值：

Answer 1

1）是-1/2

2)xy + yz + xz平方可算得：x2y2 + y2z2 + x2z2=1/4

x^2 + y^2 + z^2 平方可得：x^4 + y^4 + z^4=1/2