1、学业水平训练计算sin 43cos 13sin 13cos 43的值等于_解析:原式sin(4313)sin 30.答案:函数ysin(2x)sin(2x)的最小值为_解析:ysin(2x)sin(2x)sin 2xcoscos 2xsinsin 2xcoscos 2xsinsin 2x,y的最小值为.答案:已知为锐角,且sin(),则sin _解析:由为锐角,且sin(),可求得cos().又sin sinsin()coscos()sin.答案:若cos ,sin ,(,),(,2),则sin()的值为_解析:(,),cos ,sin ;又(,2),sin ,cos .sin()sin co
2、s cos sin ()().答案:已知sin ,sin(),均为锐角,则等于_解析:由条件知cos ,cos()(因为0,),所以sin sin ()sin cos()cos sin()(),又为锐角,所以.答案:函数f(x)sin 2xcos 2x的最小正周期是_解析:f(x)sin 2xcos 2x2(sin 2xcoscos 2xsin)2sin(2x)最小正周期T.答案:已知sin ,(,),cos ,(,),求sin()、sin()的值解:由sin ,(,),得cos .又由cos ,(,),得sin .所以sin()sin cos cos sin ()()().sin()sin
3、cos cos sin ()()().已知:,且cos(),求cos ,sin 的值解:因为,所以0.因为cos(),所以sin().所以sin sinsin()coscos()sin,cos coscos()cossin()sin.高考水平训练已知8sin 5cos 6,sin(),则8cos 5sin _.解析:设8cos 5sin x,又8sin 5cos 6,所以22得6480sin()25x236.又sin(),所以x2100,所以x10.答案:10已知向量an(cos,sin)(nN*),|b|1,则函数y|a1b|2|a2b|2|a3b|2|a141b|2的最大值为_解析:设b(
4、cos ,sin ),所以y|a1b|2|a2b|2|a3b|2|a141b|2ab22(cos,sin)(cos ,sin )ab22(cos,sin)(cos ,sin )2822cos(),所以y的最大值为284.答案:284求函数f(x)sin(x20)sin(x80)的最值解:f(x)sin(x20)sin (x20)60sin(x20)sin(x20)cos 60cos(x20)sin 60sin(x20)cos(x20)sin(x20)cos(x20)sin(x50)所以当sin(x50)1时,f(x)max,当sin(x50)1时,f(x)min.4求2sin 50sin 10(1tan 10)的值解:原式sin 80(2sin 50sin 10)cos 102sin 50cos 10sin 10cos(6010)2(sin 50cos 10sin 10cos 50)2sin(5010)2sin 602.