IIa > 0, b > 0 a + b2ab a = b( ) ( ) = a + b 2ab= (a b)2 0a b = 0 a = b//III IIB1x > 0 x +1xx +1x 2

x 1x= 2x +1x 2 x +1x2 x +1x2x +1x 2 x +1x2x +1x3 x +1x 2x +1x 2 x +1x= 2 x 2xx ()x2x +1x 2

x 1x= 2x =1xx = 1 x +1x2x > 02xx2+ x + 1a > 0, b > 0( )2xx2+ x + 1x 2x 2x( ) 0 x> 0x 0 x32xx2+ x + 1 1x1x=2x + 1 +1xx( ) = x +1x+ 12

x 1x+ 1 = 3( )3 32x + 1 +1x22x + 1 +1x232xx2+ x + 1=2x + 1 +1x xx > 0 x +1x+ 12

x 1x+ 1= 3 x > 0x =1xx = 12xx2+ x + 1=2x + 1 +1x

23x = 12xx2+ x + 123(x = 1)4http://www.hmg-gen.com/magdai@hmg-gen.com5