吾问吾知2009-02-14TA获得超过280个赞关注解;XY+Z=(X+Z)(Y+Z)Z=(X+Y+Z)zX+Y+Z=1故XYZ≤[(X+Y+Z)/3]³=1/27当且仅当X=Y=Z=1/3时取等号即XYZ的最大值是1/27;