高考数学复习第四章三角函数解三角形4.5简单的三角恒等变换第二课时简单的三角恒等变换理市赛课公开课一.pptx

,4.5,简单三角恒等变换,第,2,课时简单三角恒等变换,1/55,课时作业,题型分类深度剖析,内容索引,2/55,题型分类深度剖析,3/55,题型一三角函数式化简与求值,答案,解析,4/55,答案,解析,4,5/55,(1),三角函数式化简明遵照,“,三看,”,标准，一看角，二看名，三看式子结构与特征,.,(2),三角函数式化简明注意观察条件中角之间联络,(,和、差、倍、互余、互补等,),，寻找式子和三角函数公式之间共同点,.,思维升华,6/55,1,答案,解析,7/55,答案,解析,8/55,题型二三角函数求值,命题点,1,给值求值问题,答案,解析,9/55,为锐角，,cos,cos(,),cos(,)cos,sin(,)sin,10/55,(2)(,广东,),已知,tan,2.,解答,11/55,解答,12/55,答案,解析,命题点,2,给值求角问题,13/55,答案,解析,14/55,tan,tan,(,),15/55,引申探究,答案,解析,cos(,),cos,cos,sin,sin,16/55,(1),给值求值问题关键在,“,变角,”,，经过角之间联络寻找转化方法；,(2),给值求角问题：先求角某一三角函数值，再求角范围确定角,.,思维升华,17/55,答案,解析,即,sin,cos,cos,sin,cos,，,18/55,答案,解析,19/55,所以,sin(,),sin,(,),2,sin(,)cos 2,cos(,)sin 2,20/55,cos(,),cos,(,),2,cos(,)cos 2,sin(,)sin 2,21/55,(1),求,f,(,x,),定义域与最小正周期；,解答,题型三三角恒等变换应用,22/55,解答,23/55,24/55,三角恒等变换应用策略,(1),进行三角恒等变换要抓住：变角、变函数名称、变结构，尤其是角之间关系；注意公式逆用和变形用,.,思维升华,25/55,解答,(1),求,f,(,x,),最小正周期；,由已知，,26/55,解答,27/55,(1),讨论形如,y,a,sin,x,b,cos,x,型函数性质，一律化成,y,sin(,x,),型函数,.,(2),研究,y,A,sin(,x,),型函数最值、单调性，可将,x,视为一个整体，换元后结合,y,sin,x,图象处理,.,化归思想和整体代换思想在三角函数中应用,思想与方法系列,9,规范解答,思想方法指导,28/55,29/55,30/55,课时作业,31/55,1,2,3,4,5,6,7,8,9,10,11,12,13,1.sin 15,sin 75,值是,.,答案,解析,sin 15,sin 75,sin 15,cos 15,32/55,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,33/55,3.,已知,R,，,sin,2cos,，则,tan 2,.,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,34/55,答案,解析,2,所以,f,(,x,),最小正周期为,2.,1,2,3,4,5,6,7,8,9,10,11,12,13,35/55,5.(,江苏扬州中学四模,),函数,y,sin,(sin,cos,)(,，,0),最,大值为,.,答案,解析,y,sin,(sin,cos,),sin,2,sin,cos,1,2,3,4,5,6,7,8,9,10,11,12,13,36/55,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,37/55,1,2,3,4,5,6,7,8,9,10,11,12,13,38/55,8,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,39/55,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,40/55,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,41/55,1,2,3,4,5,6,7,8,9,10,11,12,13,42/55,答案,解析,1,2,3,4,5,6,7,8,9,10,11,12,13,43/55,1,2,3,4,5,6,7,8,9,10,11,12,13,44/55,1,2,3,4,5,6,7,8,9,10,11,12,13,45/55,11.,已知函数,f,(,x,),sin(,x,),cos,x,.,(1),求函数,f,(,x,),最大值，并写出当,f,(,x,),取得最大值时,x,取值集合；,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,46/55,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,47/55,1,2,3,4,5,6,7,8,9,10,11,12,13,48/55,12.,已知函数,f,(,x,),cos,2,x,sin,x,cos,x,，,x,R,.,(1),求,f,(),值；,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,49/55,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,50/55,1,2,3,4,5,6,7,8,9,10,11,12,13,51/55,1,2,3,4,5,6,7,8,9,10,11,12,13,52/55,13.(,安徽,),已知函数,f,(,x,),(sin,x,cos,x,),2,cos 2,x,.,(1),求,f,(,x,),最小正周期；,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,53/55,解答,1,2,3,4,5,6,7,8,9,10,11,12,13,54/55,1,2,3,4,5,6,7,8,9,10,11,12,13,55/55,