y与x成反比例=> xy = c1 where c1 is constantz与y成正比例=> yz = c2 where c2 is constantx=8,y=1/2=> c1= 4y=1/3,z= -2=> c2=-2/3iexy = 4yz = -2/3z= -2/(3y)= -2/(3 (4/x) )= -x/6z是x 的函数when x = 16z= -8/...