Maths Problem
回答 (2)
2014-01-02 6:05 am
✔ 最佳答案
1 / sin²(2x + 30°) = 1 + tan²x1 / sin²(2x + 30°) = sec²x
1 / sin²(2x + 30°) = 1 / cos²x
sin²(2x + 30°) = cos²x
sin²(2x + 30°) = sin²(90° - x)
2x + 30° = 90° - x
3x = 60°
x = 20°
參考: fooks
2014-01-02 5:48 am
sorry, the answer is wrong
this is a MC question, 4 choose:20,25,30 and 35
this is a MC question, 4 choose:20,25,30 and 35
收錄日期: 2021-04-13 19:53:08
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20140101000051KK00108