高一三角函数计算求 具体方法!(1)cos310*tan(-108)(2)sin(5π/4)*cos(4π/5)*tan(11π/6)

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高一三角函数计算
求 具体方法!
(1)cos310*tan(-108)
(2)sin(5π/4)*cos(4π/5)*tan(11π/6)

(1)cos310°×tan(-108°)=cos(360-310)×[-tan(108°)].
=cos50°×[-tan(180°-72°)].
=cos50°×[-(-tan72°)].
=cos50°×tan72°.
(2)sin(5π/4)×cos(4π/5)×tan(11π/6)
=sin(π+π/4)×cos(π-π/5)×tan(π+5π/6)
=-sin(π/4)×[-cos(π/5)]×tan(5π/6)
=√2/2×cos36°×tan150°
=√2/2×(-√3/3)cos36°
=-√6/6×cos36°
只能做到这里