Question

设函数f(x)=1/x-b+2 若a、b、c成等差数列 则f（a）+f（c）=

Answer 1

若a、b、c成等差数列,设：a-b=c-b=k f(a)=1/(a-b)+2=1/k+2 f(c)=1/(c-b)+2=1/(-k) +2 f(a)+f(c) =1/k+2-1/k+2 =4