sin21 cos21等于几?精确啊

sin21 cos21等于几?精确啊 sin21度 cos21度 tan38度等于多少? (sin39° -sin21°)/(cos39°-cos21°) sin21°cos39°+cos21°sin39°= sin21°cos24°+cos21°sin24° sin21°cos81°-cos21°sin81°=? 求值sin21°cos24°+cos21°sin24°过程 求值sin21°cos24°+cos21°sin24°过程 sin21°cos9°+cos21°sin9°=? 求sin39°-sin21°/cos39°-cos21°的值急需过程,谢谢! (sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°) （cos^2 33°-cos^2 57°）／（sin21°－cos21°） sin21度cos5度加cos21度sin5度分之sin7度cos33度减cos7度cos7度等多少 (sin24°cos6°-sin66°sin6°)/(sin21°cos39°-cos21°sin39°)化简后得 COS21度等于多少?急……COS21度等于多少? 1.5046精确到0.0001约等于几 根号5等于几(精确到0.01)? 1除以3.14等于几精确数值