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问题: 计算:1/2(x+y)^2+1/2(x+z)^2+1/2(z-y)^2

计算:1/2(x+y)^2+1/2(x+z)^2+1/2(z-y)^2
要详细步骤

解答:

1/2*(x+y)^2+1/2*(x+z)^2+1/2*(z-y)^2=1/2*[(x^2+2xy+y^2)+(x^2+2xz+z^2)+(z^2-2zy+y^2)]=x^2+y^2+z^2+xy+xz-zy。