x-y-z=3.yz-xy-xz=3.则x²+y²+z²=?
问题描述:
x-y-z=3.yz-xy-xz=3.则x²+y²+z²=?
答
(x-y-z)^2-2(yz-xy-xz)=x^2+y^2+z^2=3
x-y-z=3.yz-xy-xz=3.则x²+y²+z²=?
(x-y-z)^2-2(yz-xy-xz)=x^2+y^2+z^2=3