一、學(xué)習(xí)目標(biāo)1.會(huì)用描點(diǎn)法畫(huà)出對(duì)數(shù)函數(shù)的簡(jiǎn)圖．(重點(diǎn))2.掌握對(duì)數(shù)函數(shù)的性質(zhì)，會(huì)解決簡(jiǎn)單的與性質(zhì)有關(guān)的問(wèn)題．二、基礎(chǔ)知識(shí)1.對(duì)數(shù)函數(shù)的圖象和性質(zhì)a的范圍0<a<1a>1圖象定義域值域性質(zhì)定點(diǎn)（，）單調(diào)性函數(shù)值的變化奇偶性自我檢測(cè)1.函數(shù)f(x)＝(a＞0且a≠1)的圖象恒過(guò)定點(diǎn)__________2.反函數(shù)指數(shù)函數(shù)y＝ax(a>0，且a≠1)與對(duì)數(shù)函數(shù)y＝logax(a自我檢測(cè)2.函數(shù)y＝log2x的反函數(shù)是三、典例剖析題型一對(duì)數(shù)函數(shù)圖象與性質(zhì)的應(yīng)用【例1】如圖，若C1，C2分別為函數(shù)y＝logax和y＝A．0<a<b<1B．0<b<a<1C．a(chǎn)>b>1D．b>a>1【變式1】函數(shù)y＝log2|x|的圖象大致為()【例2】比較下列各組值的大?。海?）log5eq\f(3,4)與log5eq\f(4,3)；（2）log1.6，log1.4；（3）log7，log7；（4）log3π，log20.8．【例6】解下列不等式（1）log21（2）loga(3x5)loga(x1)【變式2】已知log0.3(a1)log0.3(3a)，則a的取值范圍為題型三反函數(shù)的概念及其應(yīng)用【例4】設(shè)f(x)log2(1x+a1)是奇函數(shù),若函數(shù)g(x)圖象與函數(shù)f(x)圖象關(guān)于直線y【變式3】若函數(shù)是函數(shù)的反函數(shù)，則題型四對(duì)數(shù)型復(fù)合函數(shù)的單調(diào)性問(wèn)題【例4】函數(shù)的單調(diào)增區(qū)間為（

）B．C． D．【變式訓(xùn)練4】求下列函數(shù)的單調(diào)區(qū)間（1）;（2）四、課后作業(yè)1．如果函數(shù)f(x)＝logax(a>0，且a≠1)的圖象經(jīng)過(guò)點(diǎn)(4，2)，那么A．eq\f(1,4)B．eq\f(1,2)C．2D．42．設(shè)a＝log32，b＝log52，c＝log23，則()A．a(chǎn)>c>bB．b>c>aC．c>b>aD．c>a>b3.函數(shù)y＝loga(x－1)(0<a<1)的圖象大致是()ABCD4.已知函數(shù)，給出下述論述，其中不正確的（

）A．當(dāng)時(shí)，的定義域?yàn)锽．一定有最小值C．當(dāng)時(shí)，的值域?yàn)镈．若在區(qū)間上單調(diào)遞增，則實(shí)數(shù)a的取值范圍是5.若函數(shù)y＝f(x)是函數(shù)y＝ax(a>0，且a≠1)的反函數(shù)，其圖象經(jīng)過(guò)點(diǎn)(32,23)6.若函數(shù)與函數(shù)有兩個(gè)交點(diǎn)，則實(shí)數(shù)的取值范圍為7.若函數(shù)f(x)lg(x2axa1)在區(qū)間[2,)