作业帮cos39°cos9°+sin39°sin9°=
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/08 04:38:03
cos39°cos9°+sin39°sin9°=
cos39°cos9°+sin39°sin9°=
cos39°cos9°+sin39°sin9°=
[解析] cos39°cos9°＋sin39°sin9°
＝cos(39°－9°)＝cos30°＝根号3/2
cos39°cos9°+sin39°sin9°=
sin39°-sin30°cos9°/cos39°-cos30°cos9°
(sin39° -sin21°)/(cos39°-cos21°)
sin21°cos39°+cos21°sin39°=
cos51°cos9°-cos39°sin9°=
(sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°)
求sin39°-sin21°/cos39°-cos21°的值急需过程,谢谢!
(sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°)化简后得
sin21°cos81°-sin69°cos9°
求值：sin21°cos81°-sin69°cos9°
cos54°cos9°+sin54°cos81°
sin21°cos9°+cos21°sin9°=?
化简COS8°-SIN17°SIN9°/COS9°
化简COS8°-SIN17°SIN9°/COS9°
试比较sin11°和cos9°的大小
设cos31°=α,则sin39°+tan149°=
求值:(sin9°+sin6°cos15°)/(cos9°-sin6°sin15°)怎么做? 过程!
计算：(sin9°+cos15°sin6°)÷(cos9°-sin15°sin6°)