cos(-29π/6)的值为?
cos(-29π/6)的值为?
已知α为锐角,且cos(α+π6)=45,则cosα的值为( )
已知α为锐角,且cos(α+π/6)=5/13,求cosα的值
已知(sinα-cosα)/(sinα+cosα)=1/3,则cos^4(π/3+α)-cos^4(π/6-α)的值为
已知cos(π/2-α)-2cosα=sinπ,且cosα<0,则sinα的值为?
若cos(π/6+α)=√2/4,则cos(5π/6-α)的值为( )
cos(π/3-α)=1/8,则cosα+(根号3)sinα的值为____
sin^2(α)+cosαcos(π/3+α)-sin^2(π/6-α)为定值,要证明
已知sinα+sinβ+sinγ=0,cosα+cosβ+cosγ=0.则cos(α-β)的值为______.
cos(-41派/3)的值为
sin(6/π-α)=1/3,则cos(2π/3+2α)的值为
若α是锐角,且满足sin(α−π6)=13,则cosα的值为( )