tan(π/4-α)=-1/3 则sin(2α+π/4)的值

若sin (π/4+α)sin(π/4-α)=-1/8,则2sin²α+tanα-1/tanα-1的值为 已知α,β∈(0,π/2),且2tanα+3sinβ=7,tanα-6sinβ=1,则sinα= tan(π/4-α)=-1/3 则sin(2α+π/4)的值 tan(π/4-α)=-1/3 则sin(2α+π/4)的值为? tanα+1/tanα=4,则sinα*cosα=? 已知tanα/tanα-1=-1,则sinα+cosα/3sinα-2cosα sinα+cosα=4/3求tanα+1/tanα=? sinα+sinβ=1/4cosβ+cosα=1/3,tanα*tanβ= tan(a+π/4)=2,则cos2a+3sin^2a+tan a= 证明[2-2sin(α+3π/4)cos(α+π/4)]/(cos^4α-sin^4α)=(1+tanα)/(1-tanα) tan(α+β)=2/5 ,tan(β-π/4 )=1/4 ,则sin(α+π/4 )•sin(π/4 -α)= tan(α+β)=2/5 ,tan(β-π4 )=1/4 ,则sin(α+π4 )•sin(π4 -α)= β∈(0,π/4),4tan(π/2)=1-tan^2(π/2),3sinβ=sin(2α+β)…… 已知sin（α+β）=1／4,sin（α-β）=1／3,则tanα∶tanβ等于 已知α∈(π/2,π),且sinα=3/5,tan(α-β)=-1,则2cos²β-4/5tanα/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tanα+1/tanα=10/3,α属于45°到90°（开区间）,则sin(2α+π/4)= 已知tan(α+π/4)=1/3已求出tanα=-1/2求2sin²α-sin(π-α)sin[(π/2)-α]+sin²[(3π/2）+α]的值.