sinπ/6,sin1,sin3较大小[cos2=sin(π/2-2)]
证明:sin3*sin1=sin^2(2)-sin^2(1)
求证sin3°=(sin^2°-sin^1°)/sin1°
已知(sinα+sin2α+sin3α)/(cosα+cos2α+cos3α)=﹣4/tanα,且π<2α<3π/2,求
已知sinα=cos2α,α∈(π2
证明2sin(π/4+α)sin(π/4-α)=cos2α
cos2α/[sin(α-π/4)]=-根号2 /2,cosα+sinα=?
cosπ/5*cos2π/5 =(2sinπ/5*cosπ/5*cos2π/5)/(2sinπ/5) =(sin2π/5
化简 (1)、sin(α+180度)cos(-α)sin(-α-180度) (2)、sin3(-α)cos(2π+α)t
已知sin²2α+sin2αcos2α-cos2α=1,α∈(0,π)求sinα,tanα
cos2α/sin(α-π/4)=-根号2/2,则cosα+sinπα等于什么
cosπ/3+tanπ/4+3tan²π/6+sinπ/2+cosπ+sin3π/2等于?.
sin(α-4分之π)分之cos2α=—2分之根号2 求cosα+sinα