sin21°cos9°+cos21°sin9°=?

化简COS8°-SIN17°SIN9°/COS9° 1.比大小：tan21°和tan31°；2.sin21°和cos21°；3.cos21°和cos22° 求值:(sin9°+sin6°cos15°)/(cos9°-sin6°sin15°) 化简（sin15°cos9°-cos66°）/（sin15°sin9°+sin66°）的结果是? cos15°sin9°+sin6°/sin15°sin9°—cos6°= 求值(sin9°cos15°-sin24°)/(sin9°sin15°+cos24°) 化简：cos21°+cos22°+cos23°+…+cos289°． 计算：sin21°+sin22°+sin23°+…+sin288°+sin289°+sin290°= ___ ． 计算：sin21°+sin22°+sin23°+…+sin287°+sin288°+sin289°． （Sin15Cos9°—Cos66°）/（Sin15°Sin9°+Sin66°）可以化简为?要过程 急求下列三角函数值sin9°52′22″sin10°30′25″sin10°32′22″ sin6+cos15*sin9/cos6-sin15*sin9