权方和不等式 权方和不等式是一种分式不等式 a i  b i   displaystyle aibi   i   n a i m   b i m    i   n a i  m     i   n b i  m  m     m    i   n a i m   b i m    i   n a i  m     i   n b i  m     m   displaystyle begincasesdisplaystyle sum infrac aimbimgeq frac displaystyle sum inaimdisplaystyle sum inbimmmdisplaystyle sum infrac aimbimleq frac displaystyle sum inaimdisplaystyle sum inbimmendcases 取等条件 a  b   a  b       a n b n displaystyle frac abfrac abfrac anbn