1/2(x+y+z)的平方+1/2(x-y-z)(x-y+z)-z(x+y)化简为多少?_数学解答

1/2(x+y+z)的平方+1/2(x-y-z)(x-y+z)-z(x+y)化简为多少?

人气：155 ℃　时间：2020-02-15 08:52:11

解答

1/2(x+y+z)的平方+1/2(x-y-z)(x-y+z)-z(x+y)=½(x²+y²+z²+2xy+2xz+2yz)+½(x²-2xy+y²-z²)-zx-zy=½x²+½y²+½z²+xy+xz+yz+½x²-xy+...