Question

若a＜b＜c,则1/(c-b)+1/(a-c) A正数B负数C非整数D非负数

Answer 1

代入法计算啦

a=1 b=2 c=3

1/(c-b)+1/(a-c)=1/(3-2)+1/(1-3)=1-1/2=1/2 正