化简[2sin(2π+2α)/(1+cos2α)]*[sin²(3π/2-α)/cos(π-2α)]
化简:sin²αsin²β+cos²αcos²β-1/2cos2αcos2β
sin²α*sin²β+cos²α*cos²β-1/2cos2αcos2β
求sin²αsin²β+cos²αcos²β-1/2cos2αcos2β的值 化
已知sinθ+cosθ=2sinα,sinθ·cosθ=sin²β,求证:2cos2α=cos2β.
已知sin²2α+sin2αcosα-cos2α=1,α∈(0,2/π),求sinα、tanα
化简:(sinα-cosα)^2+sin4α/2cos2α 化简:sin^2x+sin^2(x+2π/3)+sin^2(
化简(sinα-cosα)^2-1/-cos2α
cos2α/[sin(α-π/4)]=-根号2 /2,cosα+sinα=?
化简:sin^2αsin^2β+cos^2αcos^2β-1/2cos2αcos2β
化简(sinα)^2*(sinβ)^2+(cosα)^2(cosβ)^2-1/2cos2αcos2β
化简sinα^2sinβ^2+cos^2cosβ^2-1/2cos2αcos2β
化简:sin²αsin²β+cos²αcos²β—1/2cos2αcos2β