sin(-17π3)=( )
证明:sinπ/9[(sinπ/9)+sin(3π/9)]=sin2(2π/9)
已知sin(3π−α)=−2sin(π2+α),则sinαcosα=( )
已知 cos π/5 =(根号5 +1)/4 求 sin π/5,sin -π/5 ,sin 4π/5 ,sin 3π/
已知(3sinα+cosα)/(3cosα-sinα)=2,则2-3sin(α-3π)sin(1.5π-α)-[cos(
若(sinθ+cosθ)/(sinθ-cosθ)=2,则sin(θ-5π)*sin(3π/2-θ)等于?
若sinα+cosαsinα−cosα=2,则sin(α-5π)•sin(3π2-α)等于( )
若(sinα+cosα)/(sinα-cosα)=2 则sin(α-5π)·sin(3π/2-α)=?
α属于(0,π/2)且2sin²α-sinαcosα-3cos²α=0求sin(α+π/4)/sin
已知sin(2α+ β)=5sinβ,求证:2sin(α+ β)=3sinα
已知sin(π/6+a)=(根号3)/3,求sin(2π/3+a)?
1.已知2sin(3π+θ)=cos(π+θ),求2sin
求证 cos(A)+ 根号3sin(A)=2sin(π/6+A)