①a>o,b>o,且a+b=1 求证（a+1/a)(b+1/b)大于等于25/4
问题描述：
①a>o,b>o,且a+b=1 求证（a+1/a)(b+1/b)大于等于25/4
②a,b属于R且a不等于b,求证|根号下{1+(a的平方)}-根号下{1+(b的平方)}|
答
1.左式=ab+a/b+1/ab+b/a
=(a2b2+a2+1+b2)/ab
=[a2b2+(1-2ab)+1]/ab
=[(ab-1)2+1]/ab
(ab-1)2+1≥25/16,0