求证:tan x/2=sin x/(1+cos x)
求证 (1—tan^2X)/(1+tan^2X)=cos^2X—sin^2X
证明(1-2sin x cos x )/(cos^2x-sin^2x)=(1-tan x)/(1+tan x)
已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x
证明1-tan^2x/1+tan^2x=cos^2x-sin^2x
求证 1+2sin x cos x ———————— cos ︿2—sin x︿2 =1+tan
求证 tan(2π-X)sin(-2π-X)cos(6π-X)/ sin(X+3π/2)*cos(X+3π/2)=-ta
求证 1+2sinxcox/cos∧2x-sin∧2x=1+tanx/1-tanx tan∧2θ-sin∧2θ=tan∧
求证(cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2
证(1/sin^2x)+(1/cos^2x)-(1/tan^2x)=2+tan^2x
证明:(1 + tan x) / (sin x + cos x) = 1 / cos x
求证 cos^8(x)-sin^8(x)=cos2x【1-1/2sin^2(2x)】
证明1/sin^x+1/cos^2x-1/tanx^2x=2+tan^2