诱导公式与同角三角公式练习例1、求下列三角函数的值.(1))316sin(;(2))945cos((3)210sin(4)330sin例2、求下列三角函数的值.(1)若a165cos,求195tan.(2)若21)3sin(,求)6cos(.(3)若a)6sin(,求)32cos(.(4)若31)cos(,求)23sin(.课题笔记:例3、化简:(1))180cos()180sin()360sin()180cos(.(2))29sin()sin()3sin()cos()211cos()2cos()cos()2sin(.用心爱心专心例4、求)34cos()322sin(nn的值.)(Zn【知识回顾】1.已知31tan,求2coscossin212.已知3tan,计算用心爱心专心(1)sin3cos5cos2sin4;(2)cossin;(3)2cossin3.已知:)sin()cot()23tan()2cos()sin()(f⑴化简)(f;⑵若是第三象限的角,且51)23cos(,求)(f的值。⑶若1860,求)(f的值。用心爱心专心