解答(1)cos(-11π/6) (2)tan9π/4 (3)sin1140°
问题描述：
解答(1)cos(-11π/6) (2)tan9π/4 (3)sin1140°
答
解答:
(1)cos(-11π/6)=cos(-11π/6+2π)=cos(π/6)=√3/2
(2)tan9π/4=tan(9π/4-2π)=tan(π/4)=1
(3)sin1140°=sin(1140°-1080°)=tan60°=√3