tan(2π/13)+4sin(6π/13)

tan(2π/13)+4sin(6π/13) Sinπ/3Tanπ/3+tanπ/6COSπ/6－Tanπ/4COSπ/2 求证2(cosθ -sinθ )/1+sinθ +cosθ =tan(π/4-θ /2)-tanθ /2 高一必修4三角函数sin420*cos750+sin(-330)*cos(-660)tan675+tan765-tan(-330)+tan(-690)sin(25π/6)+cos(25π/3)+tan(-25π/4)2.已知sin(π+α)=-1/2 计算(1)sin(5π-α) (2)sin(π/2+α) (3)cos(α-3π/2) (4)tan(π/2-α) 若sin (π/4+α)sin(π/4-α)=-1/8,则2sin²α+tanα-1/tanα-1的值为 已知α∈(0,π|2）,2tanα+3sinβ=7,且tanα-6sinβ=1,求sinα的值 已知α,β∈(0,π/2),且2tanα+3sinβ=7,tanα-6sinβ=1,则sinα= sin(π/4+α)sin(π/4-α)=1/4 求2sin^2(a) -1+tana-1/tan 求值:(1)sin(4π/3)cos(7π/6)tan(21π/4)(2)sin(23π/6)cos(-17π/4)tan(π/8)tan(3π/8)要求详细过程 求证:(sin 2x /(1-cos 2x) )·(sin x /(1+sin x))=tan (π/4-x/2). 计算4/3[cos^2(13π/6)]+3tan^2(π/6)-1/3[sin^2(2π/3)], 已知tanα/2=2求tan(α+π/4)的值(6sinα+cosα)/(3sinα-2cosα)的值已知tanα/2=2求1、tan(α+π/4)的值2、(6sinα+cosα)/(3sinα-2cosα)的值 计算（1）cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6cosπ/3-tanπ/4+3/4tan²π/6-sinπ/6+cos²π/6[tan(-150°)cos（-210°）cos420°]/cot(-600°)sin（-1050°）cos25/6π+cos25/3π+tan(-25/4π)5sinπ/2+2cos0-3sin3/2π+10cosπt 若a属于(0,π/2)试比较tanα、tan(tanα)、tan(sinα) 1.求证tanαsinα/tanα-sinα=tanα+sinα/tanαsinα2.已知sinα+cosα=-1/5(π/2 cosπ/3+tanπ/4+3tan²π/6+sinπ/2+cosπ+sin3π/2等于?. 1)tan(x/2+π/4)+tan(x/2-π/4)=2tanx（2）（1-2sinαcosα/cos²α-sin²α）=（1-tanα）/（1+tanα） 已知tan(π/4+α)=-1/2,求4cosα(sinα+cosα)/(1-tanα)