sin(π/10)cos(π/5)

sin(π/10)cos(π/5) cos sin π √ sinπ/10乘cosπ/5的值 已知cos(π/2+a)=2sin(a-π/2)求sin(π-a)+cos(a+π)/5cos(5π/2-a)+3sin 【1】化简：sin(a-5π）/cos(3π-a）×cos(π/2-a）/sin(a-3π）×cos(8π-a）/sin 已知cos(π/2+α)=sin(α-π/2) 求sin（π-α）-cos（π+α）/cos（5π/2 -α）+2sin 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α- sin(π-θ）+cos(2π-θ）/cos(5π/2-θ)+sin(3π/2+θ)=2,则sinθcosθ=_____ 已知 sinα+2cos(5π/2+α)/cos(π-α)-sin(π/2-α)=-1/4 求(sinα+cosα)平方 已知 sin(θ+kπ)=-2cos (θ+kπ) 求 ⑴4sinθ-2cosθ/5cosθ+3sinθ; ⑵(1/4) 已知α∈（π,2π） sinα+cosα=1/5 求sinα*cosα sinα-cosα 已知sin a=2cos a 计算⑴（sinα+2cosα)/(5cosα-sinα) ⑵tan(α+π/4)