已知cos(θ+π/6)=5/13,0
已知cos(θ+π/6)=5/13,0
已知θ∈(-π/2,0),cosθ=13,求sinθ+cos(θ-π/4)的值
已知cos(π/6+θ)=根号3/3,求cos(5π/6-θ)的值
已知cos(α+β)=12/13,cos(2α+β)=3/5,若β∈(0,π/2),求cosα的值.
已知cos(π/6-a)=根号3/3,求cos(5π/6+a)-cos²(π/3+a)
求值:已知sinθ+cosθ=1/5,已知θ∈(0,π).
已知α为锐角,且cos(α+π/6)=5/13,求cosα的值
已知cosθ=13,θ∈(0,π),则cos(π+2θ)等于( )
已知已知cos(π/4+x)=5/13,且0
已知(4sinθ-2cosθ)/(3sinθ+5cosθ)=6/11,求5cos^2θ/(sin^2θ+2sinθcos
已知cos(θ+π/4)=3/5,π/2
已知cos(π/4+x)=3/5 ,0