求2cos50°−3sin10°cos10°的值.

问题描述:

2cos50°−
3
sin10°
cos10°
的值.

2cos50°−
3
sin10°
cos10°
=
2cos(60°−10°)−
3
sin10°
cos10°
=
cos10°+
3
sin10°−
3
sin10°
cos10°

=
cos10°
cos10°
=1.