已知sinθ/2+cosθ/2=2根号3/5,则sinθ= ,cos2θ=
已知sinθ/2+cosθ/2=2根号3/5,则sinθ= ,cos2θ=
cos2θ=根号2/3,则sin^4θ+cos^4θ=
已知cos2θ=根号2/3,则 sin^4θ+cos^4θ的值为________.
已知sinθ+cosθ=2sinα,sinθcosθ=(sinβ)^2,求证4(cos2α)^2=(cos2β)^2
已知sinθ+cosθ=2sinα,sinθ·cosθ=sin²β,求证:2cos2α=cos2β.
2sinθ+cosθ/sinθ-3cosθ=-5,求cos2θ+4sinθ
1.已知cos2θ=根号2/3,则sin^4+cos^4的值为________.
2sinα=sinθ+cosθ,sin²β==sinθcosθ.求证cos2β=2cos2α=2cos
已知sinθ-2cosθ=0,求sin2θ-cos2θ/sinθ*cosθ 的值
已知sinθ/2+cosθ/2=2√3/3,求sinθ,cos2θ
三角数列题:sinθ sinα cosθ成等差数列,sinθ sinβ cosθ为等比数列,求证2COS2α=cos2β
已知sinθ=(2/3)根号2,cos2θ=?