sin21°cos81°+cos189°sin69°化简
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sin21°cos81°+cos189°sin69°化简sin21°cos81°+cos189°sin69°化简sin21°cos81°+cos189°sin69°化简sin21°cos81°+cos
sin21°cos81°+cos189°sin69°化简
sin21°cos81°+cos189°sin69°化简
sin21°cos81°+cos189°sin69°化简
sin21°cos81°+cos189°sin69°
=sin21°cos81°-cos9°sin69°
=sin21°sin9°-cos9°cos21°
=-cos(9+21)°
=-cos30°
=-√3/2
sin21ºcos81º+cos189ºsin69º
= sin21ºcos81º-cos9ºcos21º
= sin21ºcos81º- sin81º cos21º
-sin(81º-21º)
=-sin60 º
=-√3/2
sin21°cos81°+cos189°sin69°化简
sin21°cos81°-cos21°sin81°=?
sin21°cos81°-sin69°cos9°
求值：sin21°cos81°-sin69°cos9°
sin21°cos189°-sin69°sin9°的值为
sin21°cos189°-sin69°sin9°的值为
sin21°cos81°+sin69°cos9°化简要详解
cos54°cos9°+sin54°cos81°
三角运算cos54°cos351°+sin144°cos81°
sin21度cos81度-sin69度cos9度=?
(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°=?
求sin21°+sin22°+...+sin289°的值.
求值：sin21/4π tan(-23/6π) cos1500°