cos0615°?
cos44°32等于多少
cos135°等于多少啊在线求答案
(cos15°-cos75°)(sin75° sin15°)=?详细过程,谢谢!
图片内容是:cos180°
cos30°tan30° sin60°tan45°tan60°=
cosπ=cos180°=-1
sin13°cos17°-cos13sin17=1/2 sin140°cos20 sin50sin
cos(180° α)=? sin(180°-α)=? cos(180
附录: sin0°=cos90°=sin180°=0