201x年高中數(shù)學(xué) 3.2.2對(duì)數(shù)函數(shù)（3） 蘇教版必修

1、整理課件整理課件情境問(wèn)題：情境問(wèn)題：對(duì)數(shù)函數(shù)的定義：對(duì)數(shù)函數(shù)的定義：函數(shù)函數(shù)ylogax (a0，a1)叫做對(duì)數(shù)函數(shù)叫做對(duì)數(shù)函數(shù)對(duì)數(shù)函數(shù)的定義域?yàn)閷?duì)數(shù)函數(shù)的定義域?yàn)?0， )，值域?yàn)?，值域?yàn)镽 對(duì)數(shù)函數(shù)的圖象和性質(zhì)：對(duì)數(shù)函數(shù)的圖象和性質(zhì)：對(duì)數(shù)函數(shù)的圖象恒過(guò)點(diǎn)對(duì)數(shù)函數(shù)的圖象恒過(guò)點(diǎn)(1，0)，當(dāng)當(dāng)0a1時(shí)，對(duì)數(shù)函數(shù)在時(shí)，對(duì)數(shù)函數(shù)在(0， ) 上遞減；上遞減；當(dāng)當(dāng)a1時(shí)，對(duì)數(shù)函數(shù)在時(shí)，對(duì)數(shù)函數(shù)在(0， )上遞增上遞增函數(shù)函數(shù)ylog2(x22x2)的定義域和值域分別如何求呢？的定義域和值域分別如何求呢？ 整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：(1)函數(shù)函數(shù)ylog2x的值域是的值域是 ；(2)函數(shù)函數(shù)ylog

2、2x(x1)的值域是的值域是 ；(3)函數(shù)函數(shù)ylog2x(0 x1)的值域是的值域是 整理課件數(shù)學(xué)應(yīng)用數(shù)學(xué)應(yīng)用：例例1求函數(shù)求函數(shù)ylog2(x22x2)的定義域和值域的定義域和值域整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：(1)已知函數(shù)已知函數(shù)ylog2x的值域是的值域是2，3，則，則x的范圍是的范圍是_(2)函數(shù)函數(shù) ，x (0，8的值域是的值域是 (3)函數(shù)函數(shù) 的值域的值域 (4)函數(shù)函數(shù) 的值域是的值域是_12logyx212log (617)yxx212log (2)yx整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：例例2判斷下列函數(shù)的奇偶性：判斷下列函數(shù)的奇偶性： 1(1)lg1xyx2(2)ln( 1)yx

3、x整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：例例3已知已知loga1，試求實(shí)數(shù)，試求實(shí)數(shù)a 取值范圍取值范圍 整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：例例4已知函數(shù)已知函數(shù)yloga(1ax)(a0，a1)(1)求函數(shù)的定義域與值域；求函數(shù)的定義域與值域；(2)求函數(shù)的單調(diào)區(qū)間求函數(shù)的單調(diào)區(qū)間 整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：(3)已知函數(shù)已知函數(shù) (a0，a1)的圖象關(guān)于原點(diǎn)對(duì)稱(chēng)，那的圖象關(guān)于原點(diǎn)對(duì)稱(chēng)，那么實(shí)數(shù)么實(shí)數(shù)m (1)下列函數(shù)下列函數(shù)(1) yx1；(2) ylog2(x1)；(3) y ；(4)ylnx，其中值域?yàn)槠渲兄涤驗(yàn)镽的有的有 (請(qǐng)寫(xiě)出所有正確結(jié)論的序號(hào)請(qǐng)寫(xiě)出所有正確結(jié)論的序號(hào)) (2)函數(shù)函數(shù)ylg( 1)的圖象關(guān)于的圖象關(guān)于 對(duì)稱(chēng)對(duì)稱(chēng) 1x21x1( )log1amxf xx整理課件數(shù)學(xué)應(yīng)用：數(shù)學(xué)應(yīng)用：(4)求函數(shù)求函數(shù) ，其中，其中x ，9的值域的值域 33loglog (3 )27xyx127整理課件小結(jié)：小結(jié)：借助于對(duì)數(shù)函數(shù)的性質(zhì)研究對(duì)數(shù)型函數(shù)的定義域與值域；借助于對(duì)數(shù)函數(shù)的性質(zhì)研究對(duì)數(shù)型函數(shù)的定義域與值域； 換元