化简cosα+cos(120°-α)+cos(120+α)
cos²α+cos²(120°-α)+cosαcos(120°-α)化简
化简cosα+cos(120°-α)+cos(120+α)
化简:cos(-π-α)
求和:cos(0)+cos(α)+cos(2α)+cos(3α)+……cos(nα)
化简:cos2α-cos2β/cosα-cosβ
怎样化简cosαcos(60°-α)+1
化简:sin^2αcos^2β-cos^2αsin^2β+cos^2α-cos^2β具体步骤,
sinα+sinβ=sinγ cosα+cosβ=cosγ 证明cos(α-γ)
已知α是锐角,化简,√Cos^2α-4Cosα+4-(1-Cosα)的绝对值
化简cos平方α+cos平方(α-π/3)+cos平方(α+π/3) 急、~
(sinα+cosα)^2化简
【紧急求助】计算:cosα+cos(2π/3 +α)+cos(4π/3 +α)