试解。

来源: wxcfan123 于 2015-06-21 11:40:46 [旧帖] [给我悄悄话] 本文已被阅读：次

考虑 f(t)=sqrt(t) (x >= 0). f"(t)
LHS
因 xy+yz+zx

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.