高一数学必修正弦函数余弦函数的图象ppt课件.ppt

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1、1.4三角函数的图象与性质1.4.1正弦函数、余弦函数的图象Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.2.任意给定一个实数x，对应的正弦值（sinx）、余弦值(cosx)是否存在？惟一？问题提出1.在单位圆

2、中，角α的正弦线、余弦线分别是什么？P（x，y）OxyMsinα=MPcosα=OMEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.正、余弦函数的图象Evaluationonly.CreatedwithAspos

3、e.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.知识探究（一）：正弦函数的图象思考1：作函数图象最原始的方法是什么？思考2：用描点法作正弦函数y=sinx在[0，2π]内的图象，可取哪些点？思考3：如何在直角坐标系中比较精确地描出这些点，并画出y=sinx在[0，2π]内的

4、图象？Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.xy1-1O2ππ思考4：观察函数y=sinx在[0，2π]内的图象，其形状、位置、凸向等有何变化规律？Evaluationonly.CreatedwithA

5、spose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.思考5：在函数y=sinx，x∈[0，2π]的图象上，起关键作用的点有哪几个？x-1O2ππ1yEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfil

6、e5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.思考6：当x∈[2π，4π],[-2π，0],…时，y=sinx的图象如何？y-1xO1π2π3π4π5π6π-2π-3π-4π-5π-6π-πEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.C

7、opyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.思考7：函数y=sinx，x∈R的图象叫做正弦曲线，正弦曲线的分布有什么特点？y-1xO1π2π3π4π5π6π-2π-3π-4π-5π-6π-πEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2

8、004-2011Aspo