2cos5°−sin25°cos25°的值为 _.
问题描述:
的值为 ______. 2cos5°−sin25° cos25°
答
原式=
=2cos5°−sin25° cos25°
=2cos(30°−25°)−sin25° cos25°
=
cos25°
3
cos25°
.
3
故答案为:
3