已知sin(α+3π/4)=5/13,cos(π/4-β)=3/5,且-π/4<α<π/4,π/4<β<3π/4,
已知0<α<π/2,且3sinα=4cosα求(sin^2α+2sinαcosα)/(3cos^2α-1)求cos^2α
已知α∈(0,π/2),且2sinα-sinαcosα-3cosα=0.求[sin(α+π/4)]/[sin2α+cos
已知cos(π/4+α)=-3/5,sin(3π/4+β)=5/13且派/4
已知sin(3π/4+α)=5/13 cos(π/4-β)=3/5 ,且0
已知sin(α+π)=45,且sinαcosα<0,求2sin(α+π)+3tan(3π-α)4cos(α-3π).
已知α∈(0,π/2),且2sin²α-sinαcosα-3cos²α=0,求[sin(α+π/4)
已知sinα+cosα=三分之根号二,sinα-cosα=-4/3,且α∈(-π/2,0),计算(1+sin2α+cos
已知sin(a+x)=4/5,且sinacosa<0,求[2sin(a-π)+3tan(3π-a)]/4cos(a-3π
已知sin(α-β)cosα-cos(β-α)sinα=3/5,β是第三象限角,求sin(β+5π/4)的值
已知sinαcosα=-12/25,且3π/4
已知0<α<π/2<β<π,sinα=3/5,cos(α+β)=-4/5求cosβ
已知cos(α-β/2)= -4/5,sin(β-α/2)=5/13,且π/2