2sin^225/4π+tan^2(-11/3π)*cot(-7/4π)

求证2(cosθ -sinθ )/1+sinθ +cosθ =tan(π/4-θ /2)-tanθ /2 若sin (π/4+α)sin(π/4-α)=-1/8,则2sin²α+tanα-1/tanα-1的值为 sin(π/4+α)sin(π/4-α)=1/4 求2sin^2(a) -1+tana-1/tan 求证:(sin 2x /(1-cos 2x) )·(sin x /(1+sin x))=tan (π/4-x/2). 1.求证tanαsinα/tanα-sinα=tanα+sinα/tanαsinα2.已知sinα+cosα=-1/5(π/2 若a属于(0,π/2)试比较tanα、tan(tanα)、tan(sinα) 1)tan(x/2+π/4)+tan(x/2-π/4)=2tanx（2）（1-2sinαcosα/cos²α-sin²α）=（1-tanα）/（1+tanα） 已知2tanθ/1+tan^2θ=3/5,求sin^2(π/4+θ) 已知tan(π/4+α)=-1/2,求4cosα(sinα+cosα)/(1-tanα) 证明tan^θ-sin^2θ=tan^2θsin^2θ证明（1）tan^θ-sin^2θ=tan^2θsin^2θ（2）sin^4x+cos^4x=1-2sin^2cos^2x（31-tan^2x/1+tan^2x=cos^2x-sin^2x tan(2π/13)+4sin(6π/13) sin(2a+π/4）化简成tan 已知tan(π/4+α)=2,tanβ=1/2.⑴求tanα的值,⑵求sin(α+β)-2sinαcosβ/2sinαcosβ+cos(α+β)的值已知tan(π/4+α)=2,tanβ=1/2.⑴求tanα的值,⑵求sin(α+β)-2sinαcosβ/2sinαcosβ+cos(α+β)的值 Sinπ/3Tanπ/3+tanπ/6COSπ/6－Tanπ/4COSπ/2 (1+tan(x))/sin(2x)不定积分 β∈(0,π/4),4tan(π/2)=1-tan^2(π/2),3sinβ=sin(2α+β)…… 1+2sin(π-α)cos(4π-α)/sin²(π+α)-cos²(π-α)=tanα+1/tanα-1 tan(α+β)=2/5 ,tan(β-π/4 )=1/4 ,则sin(α+π/4 )•sin(π/4 -α)=