.已知sin(α+π/6)=3/5,π/2<α+π/6<π,求sinα
已知tanα=2,sinα+cosα<0,求[sin(2π-α)*sin(π+α)*cos(-π+α)]/[sin(3π
已知sinα是方程5x²-7x-6=0的根,求[sin(-α+3π/2)sin(π-α)tan²(2
已知α∈(0,π|2),2tanα+3sinβ=7,且tanα-6sinβ=1,求sinα的值
已知sin(x+π/6)=1/3,求sin(5π/6-x)+sin^2(π/3-x)
1.已知cos(π/6-α)=1/3,求sin(2/3π-α) 2.求证tan^2α-sin^2α=tan^2α-sin
已知6sin^2α+sinαcosα-cos^2α=0,求sin(2α+π/3)的值
化简:1、sin(x-π/3)-cos(x+π/6)+√3cosx=?2、已知,sinα+sinβ=√2/2,求cosα
已知sin(π+α)=根号3/2,求sin(3/4π-α)
已知sin(π/6+a)=(根号3)/3,求sin(2π/3+a)?
已知sin(π/3 -α)=1/5求sin(2π/3 +α)和cos(7π/6 +α)的值
已知sin(3π−α)=−2sin(π2+α),则sinαcosα=( )
已知cos(π/2+α)=sin(α-π/2) 求sin(π-α)-cos(π+α)/cos(5π/2 -α)+2sin