2sin50°+cos10°(1+3tan10°)1+cos10°=_．
问题描述：
=______． 2sin50°+cos10°(1+
tan10°)
3
1+cos10°
答
原式=
=2sin50°+cos10°•
cos10°+
sin10°
3
cos10°
cos5°
2
=2sin50°+2sin40°
cos5°
2
=2
sin(50°+45°)
2
cos5°
2
=2．2
cos5°
2
cos5°
2
故答案为：2．