若sin(π3−α)=13,则cos(5π6−α)的值为( )
若α是锐角,且满足sin(α−π6)=13,则cosα的值为( )
已知(sinα-cosα)/(sinα+cosα)=1/3,则cos^4(π/3+α)-cos^4(π/6-α)的值为
若sinα+cosαsinα−cosα=2,则sin(α-5π)•sin(3π2-α)等于( )
若tanα=2,则2sinα−cosαsinα+cosα的值为( )
若cos2α/sin(α-π/4)则cosα+sinα的值为
若tan(π-α)=2,则2sin(3π+α)cos(5/2π+α)+sin(3/2π-α)sin(π-α)的值为?
sin^2(α)+cosαcos(π/3+α)-sin^2(π/6-α)为定值,要证明
已知α、β均为锐角,且tanβ=cosα−sinαcosα+sinα,则tan(α+β)的值为( )
已知sin(3π−α)=−2sin(π2+α),则sinαcosα=( )
cos(π/3-α)=1/8,则cosα+(根号3)sinα的值为____
若cos2α/sin(α-π/4)=-√2/2,则cosα+sinα的值为?
已知tan(3π-α)=2,则sin(-3π+α)+cos(π-α)/-cos(π+α)+sin(-α)的值为