数学化简cos2α+2sin^2α 急

数学化简cos2α+2sin^2α 急 ((1+cos2α)/(3sin2α))*((2sin^2(α))/cos2α)的化简 急 ((1+cos2α)/(3sin2α))*((2sin^2(α))/cos2α)的化简 ((1+cos2α)/(3sin2α))*((2sin^2(α))/cos2α)的化简 请懂数学的进来sinα^2=sin(π/4+α)×sin(π/4-α)+1-cos2α/2该怎么化简?请注意其中（1-cos2α）/2不是分开的 sin²α*sin²β+cos²α*cos²β-1/2cos2αcos2β=（1-cos2α）/2*（1-cos2β）/2+（1+cos2α）/2*（1+cos2β）/2-1/2cos2α*cos2β=1/4（1+cos2α*cos2β-cos2α-cos2β）+1/4（1+cos2α*cos2β+cos2α+cos2β）-1/2cos2α*cos2β=1/4+1/ 证明:1-cos2α/sinα=2sinα 化简:(sinα)^2+(sinβ)^2-(sinα)^2(sinβ)^2+cos2αcos2β 化简根号下1-2sinα2cos2-根号下1-sin²2为多少 化简(sinα-cosα)^2-1/-cos2α 化简cos2(-α)-tan(2π+α)/sin(-α) sinα-cosα=1/2 求cos2α cosα=2sinα则cos2α= 根号下1减sin(π+2)cos(π+2)化简是多少啊A sin2-cos2 B cos2-sin2 C +-(sin2-cos2) D sin2+cos2 2cos2α-1/1-2sinα2 化简 化简根号下(2+cos2-sin^21) 化简根号2+cos2-sin²1的结果是 己知sin^2θ=sinα cosα 求cos2θ=2sin(45°-α) cos(45°+α) 急!~~