求sin80-√3cos80-2sin20
问题描述：
求sin80-√3cos80-2sin20
答
sin80°-√3cos80°-2sin20°
=2(1/2sin80°-√3/2cos80°-sin20°)
=2(sin80°cos60°-cos80°sin60°-sin20°)
=2[sin(80°-60°)-sin20°]
=2(sin20°-sin20°)
=0