(X+1/Y)(Z+1/X)(Y+1/Z)=XYZ+1/(XYZ)+X+Y+Z+1/X+1/Y+1/Z=XYZ+1/(XYZ)+4+1+7/3=4*1*7/3得到：XYZ+1/(XYZ)=2,解得XYZ=1 参考资料里有其他人做的原题
