高中数学正弦定理和余弦定理课件新人教必修.ppt

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1、第7课时　正弦定理和余弦定理Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.定理正弦定理余弦定理内容__________________＝2R(R为△ABC外接圆半径)a2＝________________，b2＝________________，c2＝____________________．b2＋c2－2bc·cosAc2＋a2－2ca·cosBa2＋b2－2ab·cosCEvaluationonly.Crea

2、tedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.变形形式①a＝_______，b＝_______，c＝________；②sinA＝___，sinB＝___，sinC＝____；③a∶b∶c＝___________________；cosA＝_______；cosB＝_______；cosC＝_______.2RsinA2RsinB2RsinCsinA∶sinB∶sinCEvaluationonly.CreatedwithAspose.Slidesfor.

3、NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.答案：BEvaluationonly.Createdwit

4、hAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.答案：BEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.答案：直角三角

5、形Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.1．利用正弦定理可解决以下两类三角形：一是已知两角和一角的对边，求其他边角；二是已知两边和一边的对角，求其他边角．Evaluationonly.CreatedwithAsp

6、ose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.2．利用余弦定理可解两类三角形：一是已知两边和它们的夹角，求其他边角；二是已知三边求其他边角．由于这两种情形下的三角形是唯一确定的，所以其解也是唯一的．Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesf

7、or.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Eva