已知α∈(0,π/4) sin(π/4-α)=7/25 则cos2α
已知sin(π/4-α)=5/13 α∈(0,π/4) 求cos2α
已知sinα=cos2α,α∈(π2
已知sin(π/4-α)=5/13,α∈(0,π/4) 求cos2α/cos(π/4+α)
已知sin²2α+sin2αcos2α-cos2α=1,α∈(0,π)求sinα,tanα
已知tan[α+π/4]=2,求cos2α+3sin²α的值
已知sin(α-π/4)=(7√2)/10,cos2α=7/25,求sinα及tan(α+π/3)
已知4sin方α+6sinα-cos方α-3cosα=0,求cos2α-sin2α / (1-cos2α)·(1-tan
已知sinθ+cosθ=2sinα,sinθcosθ=(sinβ)^2,求证4(cos2α)^2=(cos2β)^2
已知α为第二象限角,且sin(α减π/4)+√2 *cos2α=0,求sinα+cosα的值
若cos2α/sin(α-π/4)则cosα+sinα的值为
证明2sin(π/4+α)sin(π/4-α)=cos2α
cos2α/[sin(α-π/4)]=-根号2 /2,cosα+sinα=?