> 数学 >
2sin20°+cos10°+tan20°sin10°=______.
人气:426 ℃ 时间:2020-02-06 07:51:13
解答
2sin20°+cos10°+tan20°sin10°
=2sin20°+cos10°+
sin20°sin10°
cos20°

=
2sin20°cos20°+cos10°cos20°+sin20°cos10°
cos20°

=
sin40°+cos10°
cos20°

=
cos50°+cos10°
cos20°

=
2cos30°•cos20°
cos20°

=2cos30°
=
3

故答案为:
3
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版