求sin^2α+sin^2(π/3 +α)+sin^2(π/3 -α)
已知tanα=2,sinα+cosα<0,求[sin(2π-α)*sin(π+α)*cos(-π+α)]/[sin(3π
α属于(0,π/2)且2sin²α-sinαcosα-3cos²α=0求sin(α+π/4)/sin
sinα=-2cosα,求sin^2α-3sinαcosα+1
已知sin(π+α)=根号3/2,求sin(3/4π-α)
已知3sinα cosα=0,求 3cosα 5sinα/sinα-cosα与sin²α 2sinα
sin(α+β)=2/3,sin(α-β)=3/5,sinα+sinβ=1/2,求cos(α+β)/2*sin(α-β)
已知sin(α+β)=2/3,sin(α-β)=3/5,sinα+sinβ=1/2,求cos[(α+β)/2]*sin[
已知3sin^2α—2sinα+2sin^2β=0 求sin^2α+sin^2β的取值范围
已知3(sinα)^2-2sinα+2(sinβ)^2=0,试求(sinα)^2+(sinβ)^2的取值范围
已知:3sin^2α+2sin^2β=2sinα,求sin^2α+sin^2β的值
三角函数的方程已知3sin²α+2sin²β=2sinα,求sin²α+sin²
已知3sin²α-2sinα+2sin²β=0,试求sin²α+sin²β的取值