x-z=x-y+y-z=2√2;
x2+y2+z2-xy-yz-zx=((x-y)²+(x-z)²+(y-z)²)/2=(√2+1)²/2+(√2-1)²/2+8/2=4+3=11;不对，答案是5，箐优网的答案是7x-z=x-y+y-z=2√2;x2+y2+z2-xy-yz-zx=((x-y)²+(x-z)²+(y-z)²)/2=(√2+1)²/2+(√2-1)²/2+8/2=4+3=7;最后一步刚写错了哦，那答案又错了？！谢谢