已知sinθ=(2/3)根号2,cos2θ=?
已知sinθ=(2/3)根号2,cos2θ=?
已知sinθ/2+cosθ/2=2根号3/5,则sinθ= ,cos2θ=
已知cos2θ=根号2/3,则 sin^4θ+cos^4θ的值为________.
1.已知cos2θ=根号2/3,则sin^4+cos^4的值为________.
cos2θ=根号2/3,则sin^4θ+cos^4θ=
求几道高一数学题计算1.已知sinθ/2 + cosθ/2 = 2根号3,求sin2θ 和 cos2θ值2.已知tanα
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.
已知sinθ+sin2θ=1,求3cos2θ+cos4θ-2sinθ+1的值.
已知sinθ/2+cosθ/2=2√3/3,求sinθ,cos2θ
已知θ为第二象限角,sinθ+cosθ=根号3/3,则cos2θ=
已知cos2θ=~1/2 求cosθ~sinθ的值