已知sin(θ-π/6)=5/13,（π/6＜θ＜π/2）,则cosθ=

已知(4sinθ-2cosθ)/(3sinθ+5cosθ)=6/11,求5cos^2θ/(sin^2θ+2sinθcos 已知 sin(θ+kπ)=-2cos (θ+kπ) 求 ⑴4sinθ-2cosθ/5cosθ+3sinθ; ⑵(1/4) 已知cos(θ+π/6)=-5/13,θ∈(π/2,π),则sin(θ+π/6)的值 sin(π-θ）+cos(2π-θ）/cos(5π/2-θ)+sin(3π/2+θ)=2,则sinθcosθ=_____ 已知tanθ=3,求(3cosθ-5sin^2θcosθ)/sin(π-θ)的值 1.已知2sin(3π+θ）=cos(π+θ）,求2sin 若（sinθ+cosθ）/（sinθ-cosθ）=2,则sin（θ-5π）*sin（3π/2-θ）等于? ①化简[sin(2π+α)*cos(7π-α)]/cos(-α)②已知cosθ=-3/5,θ∈(π/2,π),求sin( 已知sinθ-cosθ=1/2,(0＜θ＜π/2),求下列各式的值(1)sin³θ+cos³θ (2 已知6sin^2θ+sinθcosθ-2cos^2θ=0,θ∈[π/2,π]求cos2θ的值 已知tgθ／2=1／2,则cos（π-θ）*sin（π-θ）／cos（2π-θ）*[sin（3π／ 已知sinθ+cosθ=1/5,且π/2≤θ≤3π/4,则cos^2-θsin^2θ的值