sinα=1/3 cos2α=
来源：学生作业帮助网 编辑：六六作业网 时间：2024/11/16 17:56:59
sinα=1/3cos2α=sinα=1/3cos2α=sinα=1/3cos2α=sinα=1/3cos2α=1-2sin^2α=1-2/9==7/9=1-2(sina)^2=7/9
sinα=1/3 cos2α=
sinα=1/3 cos2α=
sinα=1/3 cos2α=
sinα=1/3
cos2α=1-2sin^2α=1-2/9==7/9
=1-2(sina)^2=7/9
sin²α*sin²β+cos²α*cos²β-1/2cos2αcos2β=（1-cos2α）/2*（1-cos2β）/2+（1+cos2α）/2*（1+cos2β）/2-1/2cos2α*cos2β=1/4（1+cos2α*cos2β-cos2α-cos2β）+1/4（1+cos2α*cos2β+cos2α+cos2β）-1/2cos2α*cos2β=1/4+1/
sinα=1/3 cos2α=
证明:1-cos2α/sinα=2sinα
已知cos2α-cos2β=1/4,那么sin(α+β)sin(α-β)=?
sinαcosαcos2α=
若tan(π-α)=1/3,则cos2α/2sinαcosα+cos2α的值为
sinα/tanα=,1/(cos2α) -1=
sinα-cosα=1/2 求cos2α
知cos2α=1/4 ,sin平方α=?
求证3+cos4α-4cos2α=(8sinα)^4证（1-cos2α)/(1+cos2α)=tan²α(1+sin2α)/(cosα+sinα)=cosα+sinα
求证：cos2αcos2β=1/2{cos2（α+β）+cos2(α-β)}
3sinα+cosα=0,则1/cos2α+sin2α=
α是锐角,sinα-cosα=1/3,cos2α=
若tanα=√3,求cos2α-cos^2α/sin^2α-1
设α∈(0,π),sinα-cosα=-1/3,求cos2α
设α∈(0,π),sinα-cosα=-1/3,求cos2α
已知COS2α=-1/3,则SIN^6α+COS^6α=
若α是锐角,且sin(α-π/6)=1/3,求cos2α