1-2cos^2(π/8)
1-2cos^2(π/8)
cos x>-1/2
【1】化简:sin(a-5π)/cos(3π-a)×cos(π/2-a)/sin(a-3π)×cos(8π-a)/sin
cos(x)=-(1/8),π< x < (3π)/2
(1+sinα+cosα)*[sin(α/2)-cos(α/2)]/√(2+2cosα)化简 (3/2*π
化简:根号1-cos(2π+a)/1+cos(2π+a) +根号1+cos(2π-a)/1-cos(2π-a) (π
化简:根号下1-cos(2π+θ)/1+cos(2π+θ)+根号下1+cos(2π+θ)/1-cos(2π+θ)( π
计算cos平方π/12-1/2
1-sin2a-cos^2(a-π/4)
化简:根号1-cos(2π+a)/1+cos(2π+a) +根号1+cos(2π-a)/1-cos(2π-a)
化简:[1+2sin(α+2π)*cos(α-2π)]/[sin(α+4π)+cos(α+8π)]
已知sinαcosα=1/8,且α是第三象限角,求(1-cos^2 α)/(sinα-cosα)-(sinα+cosα)