设a>b>c.(a-c)*(1/a-b+1/b-c)大于等于k.则k的最大值为、?

设a>b>c.(a-c)*(1/a-b+1/b-c)大于等于k.则k的最大值为、?
设a>b>c.(a-c)*(1/a-b+1/b-c)大于等于k.则k的最大值为、?

设a>b>c.(a-c)*(1/a-b+1/b-c)大于等于k.则k的最大值为、?
(a-c)*(1/a-b+1/b-c)>=k
(a-b+b-c)*(1/a-b+1/b-c)
=[1+(b-c)/(a-b)+1+(a-b)/(b-c)]
>=4
则k的最大值为4