數學SIN COS一問.........
回答 (1)
2013-01-31 4:55 am
✔ 最佳答案
cos(180 - x) = -sin x因此 (cos 0)^2 + (cos 2)^2 + (cos 4)^2 +...+ (cos 180)^2
= (cos 0)^2 + (cos 2)^2 + (cos 4)^2 +...+ (cos 90)^2
(sin 0)^2 + (sin 2)^2 + ... + (sin 88)^2
= 1 + 1 + ... + 1 + 1
= 45
收錄日期: 2021-04-27 17:43:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130129000051KK00312