sin21°cos81°-cos21°sin81°=?
来源：学生作业帮助网 编辑：六六作业网 时间：2025/01/24 07:21:05
sin21°cos81°-cos21°sin81°=?sin21°cos81°-cos21°sin81°=?sin21°cos81°-cos21°sin81°=?sin21°cos81°-cos21°
sin21°cos81°-cos21°sin81°=?
sin21°cos81°-cos21°sin81°=?
sin21°cos81°-cos21°sin81°=?
sin21°cos81°-cos21°sin81°
=sin(21°-81°)
=sin(-60°)
=-sin60°
=-(√3)/2
负2分之根号3
sin21°cos81°-cos21°sin81°=?
sin21°cos81°-sin69°cos9°
求值：sin21°cos81°-sin69°cos9°
sin21°cos81°+cos189°sin69°化简
(sin39° -sin21°)/(cos39°-cos21°)
sin21°cos39°+cos21°sin39°=
sin21°cos24°+cos21°sin24°
求值sin21°cos24°+cos21°sin24°过程
求值sin21°cos24°+cos21°sin24°过程
sin21°cos9°+cos21°sin9°=?
sin21°cos81°+sin69°cos9°化简要详解
(sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°)
求sin39°-sin21°/cos39°-cos21°的值急需过程,谢谢!
（cos^2 33°-cos^2 57°）／（sin21°－cos21°）
(sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°)化简后得
sin21 cos21等于几?精确啊
cos54°cos9°+sin54°cos81°
三角运算cos54°cos351°+sin144°cos81°