proof of inequalities-- urgent (20 points)

👨🏻‍🏫 學術台數學

CHING WAI

2008-03-15 10:38 pm

1. Prove the following inequality when a>0 and b>0. Then state the conditions for which the LHS equals the RHS.
(a+b)(1/a + 1/b ) >= 4

回答 (2)

Audrey Hepburn

2008-03-15 10:53 pm

✔ 最佳答案

As follows~~~
As follows~~~

圖片參考：http://i182.photobucket.com/albums/x4/A_Hepburn_1990/A_Hepburn09Mar151453.jpg?t=1205564012

參考: Myself~~~

👍 0 👎 0

louis

2008-03-15 11:07 pm

By Cauchy-Schwarz;s Inequality
(A＋B)(1/A＋1/B)＞＝square of【開方A(1/開方A)＋開方B(1/開方B)】
(A＋B)(1/A＋1/B)＞=square of (1＋1)=4
The inequality holds iff A=B

參考: 自己math底

👍 0 👎 0