
人教高中數(shù)學(xué)A版必修一《對(duì)數(shù)函數(shù)》指數(shù)函數(shù)與對(duì)數(shù)函數(shù)PPT(第1課時(shí)),共41頁(yè)。
學(xué)習(xí)目標(biāo)
1.通過(guò)具體實(shí)例,了解對(duì)數(shù)函數(shù)的概念,知道對(duì)數(shù)函數(shù)與指數(shù)函數(shù)互為反函數(shù)
2.能用描點(diǎn)法畫(huà)出具體對(duì)數(shù)函數(shù)的圖象,探索并了解對(duì)數(shù)函數(shù)的單調(diào)性與特殊點(diǎn)
對(duì)數(shù)函數(shù)的概念
一般地,把函數(shù)________________________叫做對(duì)數(shù)函數(shù),其中____是自變量,函數(shù)的定義域是__________.
反函數(shù)
對(duì)數(shù)函數(shù)y=logax(a>0,且a≠1)與__________________________互為反函數(shù),它們的定義域與值域正好交換.
求與對(duì)數(shù)函數(shù)有關(guān)的函數(shù)的定義域時(shí)應(yīng)遵循的原則
(1)分母不能為0.
(2)根指數(shù)為偶數(shù)時(shí),被開(kāi)方數(shù)非負(fù).
(3)對(duì)數(shù)的真數(shù)大于0,底數(shù)大于0且不為1.
1.對(duì)數(shù)函數(shù)圖象過(guò)定點(diǎn)問(wèn)題
求函數(shù)y=m+logaf(x)(a>0,且a≠1)的圖象過(guò)定點(diǎn)時(shí),只需令f(x)=1求出x,即得定點(diǎn)為(x,m).
2.根據(jù)對(duì)數(shù)函數(shù)圖象判斷底數(shù)大小的方法
作直線(xiàn)y=1與所給圖象相交,交點(diǎn)的橫坐標(biāo)即為各個(gè)底數(shù),依據(jù)在第一象限內(nèi),自左向右,圖象對(duì)應(yīng)的對(duì)數(shù)函數(shù)的底數(shù)逐漸變大,可比較底數(shù)的大。
3.函數(shù)圖象的變換規(guī)律:
(1)一般地,函數(shù)y=f(x±a)+b(a,b為實(shí)數(shù))的圖象是由函數(shù)y=f(x)的圖象沿x軸向左或向右平移,再沿y軸向上或向下平移得到的.
(2)含有絕對(duì)值的函數(shù)的圖象一般是經(jīng)過(guò)對(duì)稱(chēng)變換得到的.
... ... ...
關(guān)鍵詞:對(duì)數(shù)函數(shù)PPT課件免費(fèi)下載,指數(shù)函數(shù)與對(duì)數(shù)函數(shù)PPT下載,.PPTX格式;










