①a>o,b>o,且a+b=1求證(a+1/a)(b+1/b)大於等於25/4 ②a,b屬於R且a不等於b,求證|根號下{1+(a的平方)}-根號下{1+(b的平方)}|

①a>o,b>o,且a+b=1求證(a+1/a)(b+1/b)大於等於25/4 ②a,b屬於R且a不等於b,求證|根號下{1+(a的平方)}-根號下{1+(b的平方)}|

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