求2cos50°−3sin10°cos10°的值.
问题描述:
求
的值. 2cos50°−
sin10°
3
cos10°
答
=2cos50°−
sin10°
3
cos10°
=2cos(60°−10°)−
sin10°
3
cos10°
cos10°+
sin10°−
3
sin10°
3
cos10°
=
=1.cos10° cos10°