Sin（一13O0度）和C0S（负六分之七十九兀）用公式求以上两个三角函数值
2019-06-24
Sin（一13O0度）和C0S（负六分之七十九兀）用公式求以上两个三角函数值
优质解答
Sin（一13O0度）
=-sin1300°
=-sin(1080°+220°)
=-sin220°
=-sin(180°+40°)
=sin40°
C0S（负六分之七十九兀）
=cos79π/6
=cos(12π+7π/6)
=cos7π/6
=cos(π+π/6)
=-cosπ/6
=-√3/2
Sin（一13O0度）
=-sin1300°
=-sin(1080°+220°)
=-sin220°
=-sin(180°+40°)
=sin40°
C0S（负六分之七十九兀）
=cos79π/6
=cos(12π+7π/6)
=cos7π/6
=cos(π+π/6)
=-cosπ/6
=-√3/2