對(duì)數(shù)函數(shù)及其性質(zhì)教案3

1、2.2.2(2)對(duì)數(shù)函數(shù)及其性質(zhì)（教學(xué)設(shè)計(jì)）（內(nèi)容：圖象與性質(zhì)應(yīng)用）教學(xué)目的：（1）進(jìn)一步理解對(duì)數(shù)函數(shù)的圖象和性質(zhì)；（2）熟練應(yīng)用對(duì)數(shù)函數(shù)的圖象和性質(zhì)，解決一些綜合問(wèn)題；（3）通過(guò)例題和練習(xí)的講解與演練，培養(yǎng)學(xué)生分析問(wèn)題和解決問(wèn)題的能力教學(xué)重點(diǎn)：對(duì)數(shù)函數(shù)的圖象和性質(zhì)教學(xué)難點(diǎn)：對(duì)對(duì)數(shù)函數(shù)的性質(zhì)的綜合運(yùn)用教學(xué)過(guò)程：一、復(fù)習(xí)回顧，新課引入：1完成下表（對(duì)數(shù)函數(shù)且的圖象和性質(zhì)）xyalog?0(?a)0?a10??a1?a圖象定義域值域性思考底

2、數(shù)是如何影響函數(shù)的（學(xué)生獨(dú)立思考，師生axyalog?共同總結(jié)）小結(jié)：當(dāng)a1時(shí)，函數(shù)單調(diào)遞增，a越大，圖象越靠近x軸；當(dāng)0a1時(shí)，函數(shù)單調(diào)遞減，a越小，圖象越靠近x軸。變式訓(xùn)練1：已知函數(shù)的圖象，xyxyxyxyaaaa4321loglogloglog????則底數(shù)之間的關(guān)系：例2：根據(jù)對(duì)數(shù)函數(shù)的圖象和性質(zhì)填空已知函數(shù)，則當(dāng)時(shí)，；當(dāng)時(shí)，xy2log?0?x?y1?x?y；當(dāng)時(shí)，；當(dāng)時(shí)，10??x?y4?x?y變式訓(xùn)練2：已知函數(shù)，則當(dāng)時(shí)