设cosα=-√5/5 π

设cosα=-√5/5 π 设α为锐角 若cos (α+π/3)=1/5则cos(α-π/6)= 设sinα=12/13,cosβ=-3/5,α,β∈(0,π)求cos(α-β) 设α属于(0,π/2),若sinα=3/5,则√2cos(α+π/4)等于 设α∈(0,π/3),β(π/6,π/2),且α,β满足5√3sinα+5cosα=8√2sinβ+√6cosβ =2 求cos(α+β )设α∈(0,π/3),β(π/6,π/2),且α,β满足53sinα+5cosα=8 /2sinβ+/6cosβ =2 求cos(α+β ) 设sin(π/4+α)+cos(π/4+α)=-1/5,则cos2α= 设tan(5π+α)=m,求[sin(-α)-cos(π+α)]的值 设tan（5π+α）=m 求sinα-cosα的值 设α∈（0,π/3) β∈（π/6,π/2) 且5/3sinα+5cosα=8 ,/2sinβ+/6cosβ =2 求cos（α+β ）设α∈（0,π/3) β∈（π/6,π/2) 且5/3sinα+5cosα=8 ,/2sinβ+/6cosβ =2 求cos（α+β ）的值且5√3sinα+5cosα=8 ,√2sinβ+√6cosβ =2看 设tan(5π+α)=m,则sin(α-3π)+cos(π-α)/sin(-α)-cos(π+α)的值为 设α是锐角,cos(α+π/6)=-1/3,则cosα=____,sin(α+5π/12)=____ 设0＜α＜β＜π/2,且cos(α+β)=-5/13,cos(α-β)=3/5,则cos2β=? 设A∈（0,π/2) 若sinα=3/5,根号2cos（α+π/2)等于不过cos 前面是 根号2 不是2 设α、β均为锐角,cosα=7分之1,cos(α+β)=-4分之5,求cosβ的值如题. 设tan(5π+α)=m,(1)求sin(α-3π)+cos(π-α)/sin(-α)-cos(π+α)的值(2)求sinα-cosα的值 设cos(α-β)=-4/5,cos(α+β)=12/13,α-β∈(π/2,π),α+β∈(3π/2,2π),求cos 设α使第三象限角,tan(π-α)=-5/12,则cos(3π/2-α)= 设α为锐角,若cos(α+π/6)=3/5,则sin(α-π/12)=