求值:(tan10°-√3)×cos10°/sin50° 求证:[sin(2α+β)]/sinα- 2cos(α+β)=sinβ/cosα 化简cosθ+cos(θ+2π/3)+cos(θ+4π/3) 证明:sin(α+β)sin(α-β)=sin^2α-sin^2β

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求值:(tan10°-√3)×cos10°/sin50° 求证:[sin(2α+β)]/sinα- 2cos(α+β)=sinβ/cosα 化简cosθ+cos(θ+2π/3)+cos(θ+4π/3) 证明:sin(α+β)sin(α-β)=sin^2α-sin^2β

求值:(tan10°-√3)×cos10°/sin50° 求证:[sin(2α+β)]/sinα- 2cos(α+β)=sinβ/cosα 化简cosθ+cos(θ+2π/3)+cos(θ+4π/3) 证明:sin(α+β)sin(α-β)=sin^2α-sin^2β
求值:(tan10°-√3)×cos10°/sin50°
求证:[sin(2α+β)]/sinα- 2cos(α+β)=sinβ/cosα
化简cosθ+cos(θ+2π/3)+cos(θ+4π/3)
证明:sin(α+β)sin(α-β)=sin^2α-sin^2β

求值:(tan10°-√3)×cos10°/sin50° 求证:[sin(2α+β)]/sinα- 2cos(α+β)=sinβ/cosα 化简cosθ+cos(θ+2π/3)+cos(θ+4π/3) 证明:sin(α+β)sin(α-β)=sin^2α-sin^2β
(tan10°-√3)×cos10°/sin50°
=(sin10°/cos10°-√3)×cos10°/sin50°
=(sin10°-√3cos10°)/sin50°
=2(cos60°sin10°-sin60°cos10°)/sin50°
=2×sin(10°-60°)/sin50°
=-2