已知sin(a-π/4）=7根号2/10,cos2a=7/25,求sina及tan(a+π/3）

来源：学生作业学帮网编辑：学帮网时间：2024/05/14 12:15:15

sin(α-45°)=√2/2(sinα-cosα)=7√2/10
→sinα-cosα=7/5
cos2α=cosα^2-sinα^2=7/25
→sinα=3/5,cosα=-4/5
tan(α+60°)=(tanα+tan60°)/(1-tanα*tan60°)=(-3/4+√3)/(1+3/4*√3）
=(48-25√3)/11

已知sin(a-π/4)=-根号2/10,0 已知sin(π/6+a)=（根号3）/3,求sin(2π/3+a)? 已知sin(A+π/4)=7根号2/10,A属于(π/4,π/2)求cosA的值已知sin（a—π/4）=7倍根号2/10,cos2a=7/25,求sina及tan（a+π/3）的值已知sin(a-π/4）=7根号2/10,cos2a=7/25,求sina及tan(a+π/3）已知sin(a-π/4）=7根号2/10,cos2a=7/25,求sina及tan(a+π/3）已知sin(π/4-a)sin(π/4+a)=六分之根号二(0 已知cos(a-π/6）+sina=4根号下3/5,则sin(a+7π/6)=? 已知sin(3π-a)=根号2 sin（π-b）,根号3 cos（-a）=-根号2 cos（π+b）,且0＜a＜π 0＜b＜π求sin a cosa 已知sin（α-π/4）=（7根号2）/10,cos2α=7/25,求sinα及tan（α+π/3）的值. 已知x+y=根号2sin(a+π/4),x-y=根号2sin(a-π/4),求证x^2+y^2=1 已知x+y=根号2sin(a+π/4),x-y=根号2sin(a-π/4),求证x^2+y^2=1 已知sin(a+π/3)+sina=-(4倍根号下3)/5,-π/2 已知sin(a+π/3)+sina=-4根号3/5,-π/2 已知sin(a+π/3)+sina=-4根号3/5 -π/2 已知tanA=-根号2/2,求（2cos^2×A/2—sinA—1）÷（根号2sin(A+π/4)) 已知a、β∈（0,2分之π）,且sina=根号5分之1,sinβ=根号10分之1,求a+β是, 已知tanθ=(sin α-cos α)/(sin α+cos α) a,θ(0,π/2) 求证cos(3/2兀+ α) -sin(5π/2-α）=根号2sin(θ-4π）