As follows:
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maths~~~~~~~`
2010-01-20 6:57 am
回答 (1)
2010-01-20 7:05 am
✔ 最佳答案
sin^2 89 = cos^2 1sin^2 90 = 1
sin^2 45 = 0.5
sin^2 1 + sin^2 2 + .... + sin^2 89 + sin^2 90
= sin^2 1 + cos^2 1 + sin^2 2 + cos^2 2 +.... + 1
= 44(1)+sin^2 45 +1
= 45.5
收錄日期: 2021-04-23 20:39:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100119000051KK01732