【正文】
y | y>0}值域{y | y>0}在R上單調(diào)遞增在R上單調(diào)遞減非奇非偶函數(shù)非奇非偶函數(shù)函數(shù)圖像都過定點(0,1)函數(shù)圖像都過定點(0,1)當(dāng)x0時,y1當(dāng)x0時,0y1當(dāng)x0時,0y1當(dāng)x0時,y1(1)對數(shù)函數(shù)的概念:函數(shù),且叫做對數(shù)函數(shù),其中是自變量,函數(shù)的定義域是(0,+∞).(2)對數(shù)函數(shù)的圖像和性質(zhì):a10a1定義域{x| x>0}定義域{x| x>0}值域為R值域為R在(0,+∞)上遞增在(0,+∞)上遞減函數(shù)圖像都過定點(1,0)函數(shù)圖像都過定點(1,0)當(dāng)x1時,y0當(dāng)0x1時,y0當(dāng)x1時,y0當(dāng)0x1時,y0(1)冪函數(shù)定義:一般地,形如的函數(shù)稱為冪函數(shù),其中為常數(shù).(2)冪函數(shù)性質(zhì)歸納:①所有的冪函數(shù)在(0,+∞)都有定義,并且圖像都過點(1,1),不過第四象限;②時,冪函數(shù)的圖像通過原點,并且在區(qū)間上是增函數(shù);③時,冪函數(shù)的圖像在區(qū)間上是減函數(shù).與x軸、y軸沒有交點;④當(dāng)為奇數(shù)時,為奇函數(shù);當(dāng)為偶數(shù)時,為偶函數(shù)。習(xí)題1.( )A. B. C. D.(,且)的圖像經(jīng)過二、三、四象限,則一定有( )