2sin^2αcosα-sin(3/2π-α)cos2α
(2sinα+cosα)/(sinα-3cosα)=-5 求cos2α
2sin2α-cos2α+sinαcosα-6sinα+3cosα=0,求2cos2α+sinαcosα/1+tanα.
cos2α/[sin(α-π/4)]=-根号2 /2,cosα+sinα=?
2sinα=sinθ+cosθ,sin²β==sinθcosθ.求证cos2β=2cos2α=2cos
化简(sinα-cosα)^2-1/-cos2α
化简:sin^2αsin^2β+cos^2αcos^2β-1/2cos2αcos2β
化解sin^2αsin^2β+cos^2αcos^2β-1/2cos2αcos2β
化简(sinα)^2*(sinβ)^2+(cosα)^2(cosβ)^2-1/2cos2αcos2β
化简:(sinα-cosα)^2+sin4α/2cos2α 化简:sin^2x+sin^2(x+2π/3)+sin^2(
Sin²αSin²β+Cos²αCos²β-1/2Cos2αCos2β
化简:sin²αsin²β+cos²αcos²β-1/2cos2αcos2β
sin²α*sin²β+cos²α*cos²β-1/2cos2αcos2β