为什么sin11π/3=sin(4π-π/3)=-sinπ/3=-根号3/2,sin(4π-π/3)=-sinπ/3我不
已知 cos π/5 =(根号5 +1)/4 求 sin π/5,sin -π/5 ,sin 4π/5 ,sin 3π/
已知sin(π/6+a)=(根号3)/3,求sin(2π/3+a)?
已知sin(π+α)=根号3/2,求sin(3/4π-α)
求证 cos(A)+ 根号3sin(A)=2sin(π/6+A)
sin(3π-α)=根号
α属于(0,π/2)且2sin²α-sinαcosα-3cos²α=0求sin(α+π/4)/sin
根号3×cosπ/12-sinπ/12=?
f(x)=2sinπ/4cosπ/4-2根号3sin^2π/4+根号3
已知sin(π/4+α)+sin(π/4-α)=根号2/3,(1)求sinα(2)求sin(α-π/4)/1-sin2α
已知函数f(x)=2根号3sin平方x-sin(2x-π/3)
化简2sin^2[(π/4)+x]+根号3(sin^x-cos^x)-1
证明:sinπ/9[(sinπ/9)+sin(3π/9)]=sin2(2π/9)