![sina cosa=五分之三,sin2a=多少](http://i.ooniu.com/i/0/3291902433/124026784/253.jpg)
sina cosa=五分之三,sin2a=多少
![sinb.cosa.cosb.tana.tanb分别等于什么](http://i.ooniu.com/i/0/623674983/2322836532/253.jpg)
sinb.cosa.cosb.tana.tanb分别等于什么
![已知tana=2求2sin2a sinacosa-3cos2a的值 中间的2说是平方,谢谢!](http://i.ooniu.com/i/0/70157698/3441392256/253.jpg)
已知tana=2求2sin2a sinacosa-3cos2a的值 中间的2说是平方,谢谢!
![sin(a b)=sinacosb cosasinb 以b=a代入,得: sin(a a)=sinacosa cos](http://i.ooniu.com/i/2/514328807/3302286425/253.jpg)
sin(a b)=sinacosb cosasinb 以b=a代入,得: sin(a a)=sinacosa cos
![有2sin^2a-sinacosa-3cos^2a=0可化为(2sina-3cosa)(sina](http://i.ooniu.com/i/1/2168603855/2058087766/253.jpg)
有2sin^2a-sinacosa-3cos^2a=0可化为(2sina-3cosa)(sina
![1 tanatanb);tan(a b)=(tana tanb)/(1-tanatanb);cos(a-b)=cosacosb](http://i.ooniu.com/i/0/1498047898/3574543861/253.jpg)
1 tanatanb);tan(a b)=(tana tanb)/(1-tanatanb);cos(a-b)=cosacosb