【正文】
??上遞減 , 在?2 ,e? ???上遞增 , ∴2min 21( ) ( ) 1g x g ee? ? ?即211≤be?. 練習(xí)三 .3 解 :( 1 )∵函數(shù)()fx圖象關(guān)于原點(diǎn)對(duì)稱, ∴對(duì)任意實(shí)數(shù)( ) ( )x f x f x有 = ,3 2 3 22 4 2 4a x b x c x d a x b x c x d\ + = + ,即2 20b x d=恒成立0 , 0bd\ = = 32( ) , ( ) 3f x a x c x f x a x c162。\ = + = +, 1x =Q時(shí) ,()fx取極小值22, 3 033a c a c且 \ + = + = ,解得1,13ac= = ⑵ 證明2( ) 1 , ( ) 0 , 1 ,f x x f x x令 得ⅱ = = = ?Q ( , 1 )x ??Q或( 1 , )x ??時(shí), ( ) 0 。 ( 1 , 1 )f x x162。 ?時(shí) , ( ) 0fx162。 , ( ) [ 1 , 1 ]fx 在\上是減函數(shù),且m a x m i n22( ) ( 1 ) , ( ) ( 1 )33f x f f x f= = = = ∴在 [ - 1 , 1] 上,122| ( ) | , , [ 1 , 1 ]3f x x x于 是≤ ?時(shí), 1 2 1 22 2 4| ( ) ( ) | | ( ) | | ( ) |3 3 3f x f x f x f x≤ ≤ + + =.