cos1°+cos2°+cos3°+...+cos180°的值为?

cos1°+cos2°+cos3°.+co180°=? cos1°+cos2°+cos3°+.+cos360° cos1°+cos2°+cos3°+...+cos179°化简 cos1°+cos2°+cos3°+.+cos359°等于多少. cos1°²+cos2°²+cos3°²+cos4°²...+cos89°²=? cos1°+cos2°+cos3°+……+cos179°+cos180°的值是( cos1°+cos2°+cos3°+...+cos²89°过程和答案!速度啊 多谢! cos1°+cos2°+cos3°+...+cos180°的值为?到底是0还是-1? cos1°+cos2°+cos3°+...+cos180°的值为? Cos1°+cos2°+cos3°+……cos89°= 求cos1°+cos2°+cos3°+...+cos178°+cos179°的值（这里的数字都是度数比如1°）求cos1°+cos2°+cos3°+...+cos178°+cos179°的值 cos1°+cos2°+cos3°+……cos180°=_______谢谢大家,给出过程吧~~~~ cos1°×cos1°+cos2°×cos2°+……+cosn (sin1°-cos1°)(sin2°-cos2°)(sin3°-cos3°)……（sin89°-cos89°）=一定要告诉我原因啊 谢谢最后得0. cos1°的二次方+cos2°的二次方+cos3°的二次方+……cos89°的二次方= 比大小cos1,cos2,cos3,cos4 cos1 cos2 cos3 cos4 的大小关系 cos1/7*cos2/7*cos3/7=?