化简:cos^4α-sin^4α+2sin^2α化简：cos^4α-sin^4α+2sin^2α

化简sin^4α+cos^4α+2sin^2α*cos^2α-1 化简sin^4α+cos^2α+sin^2α*cos^2α sin(α+π/3)+sinα=负5分之4根号3 α∈（-π/2,0）求cosα怎样从9/4*sin²α=9/4(1-cos²α)=3/4*cos²a+12/5*cosx+48/25化为cos²α+4/5*cosα-11/100=0呀sin(α+π/3)+sinα=-4√3/5sinαcosπ/3+cosαsinπ/3+sinα=-4√3/53/2*si sinα-cosα×tanα-sin^4α-sin^2α×cos^2-cos^2α 求最后结果 已知sinα-2cosα=10求(sinα-4cosα)/(5sinα+2cosα) 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) 已知sinΘ+cosΘ=2sinα,sinΘ*cosΘ=sin²β,求证：4cos²2α=cos²2β 已知sinθ+cosθ=2sinα,sinθ*cosθ=sin²β,求证：4cos²2α=cos²2β 化简sin(α-2π)+sin(-a-3π)cos(α-3π)/cos(π-α)-cos(-π-α)cos(α-4π) 化简:cos^4α-sin^4α+2sin^2α化简：cos^4α-sin^4α+2sin^2α sin^6а+cos^6а+3sin²аcos²а化简=(sin^2α+cos^2α)(sin^4α-sin^2α*cos^2α+cos^4α)+3sin^2α*cos^2α这一步的sin四次方是怎么出来的?看不懂,求这一步的详写. 化简：（1）sin^2·α+cos^4·α+sin^2·αcos^2·α（2）（1-cos^4·α-sin^4·α）/(1-cos^6·α-sin^4·α) 化简：[1+2sin(α+2π)*cos(α-2π)]/[sin(α+4π)+cos(α+8π)] 化简4sin²α-sinαcosα-3cos²α=0 求证:4sinαcosα(cos^2α-sin^2α)=sin4α 求证：4sinαcosα(cos^2α-sin^2α)=sin4α tanα=2,求3sinα+4cosα.2sinα-cosα 若tanα=2,则(4sinα+cosα)/(sinα+cosα) =