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《高中數(shù)學(xué)必修五課件：2.4(等比數(shù)列(一)）(人教A版必修5)》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在教育資源-天天文庫(kù)。
1、2.4等比數(shù)列（一）Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.掌握等比數(shù)列的定義，理解等比數(shù)列的通項(xiàng)公式及推導(dǎo)過(guò)程，并能應(yīng)用等比數(shù)列的定義及通項(xiàng)公式解決問(wèn)題．Evaluationonly.Createdwit
2、hAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.1．如果一個(gè)數(shù)列從第2項(xiàng)起，每一項(xiàng)與它的前一項(xiàng)的比等于同一個(gè)常數(shù)，那么這個(gè)數(shù)列叫做________數(shù)列，這個(gè)常數(shù)叫做等比數(shù)列的________，公比通常用字母q表示(q≠0)．答案：等比 公比自學(xué)導(dǎo)引Evaluati
3、ononly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.2．如果在a與b中間插入一個(gè)數(shù)G，使a，G，b成等比數(shù)列，那么G叫做a與b的________．答案：等比中項(xiàng)3．等比數(shù)列的通項(xiàng)公式為_(kāi)_______．答案：an＝a1qn－1Eval
4、uationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.1．等比數(shù)列的公比能否為0，首項(xiàng)能否為0?答案：等比數(shù)列的首項(xiàng)，公比都不為0.2．若G2＝ab，則a，G，b一定成等比數(shù)列嗎？答案：不一定，因?yàn)槿鬐＝0，且a，b中至少有一個(gè)
5、為0，使G2＝ab，根據(jù)等比數(shù)列的定義，a，G，b不成等比數(shù)列．當(dāng)a，G，b全不為零時(shí)，若G2＝ab，則a，G，b成等比數(shù)列．自主探究Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.A．a(chǎn)n＝a3qn－2B．a(chǎn)n＝
6、a3qn－1C．a(chǎn)n＝a3qn－3D．a(chǎn)n＝a3qn－4解析：∵a3qn－3＝a1·q2·qn－3＝aqn－1＝an.答案：C預(yù)習(xí)測(cè)評(píng)Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.2．如果－1，a，b，c，－9成
7、等比數(shù)列，那么( )A．b＝3，ac＝9B．b＝－3，ac＝9C．b＝3，ac＝－9D．b＝－3，ac＝－9解析：∵b是－1，－9的等比中項(xiàng)，∴b2＝9，b＝±3，又因?yàn)榈缺葦?shù)列奇數(shù)項(xiàng)符號(hào)相同，得b＜0，故b＝－3，而b又是a，c的等比中項(xiàng)，故b2＝ac，ac＝9，故選B答案：BEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.
8、NET3.
