請詳細步驟教我計以下三條.
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急! F5 Trigonometry Solve 唔識做 ?
2013-06-05 8:44 am
回答 (1)
2013-06-05 2:47 pm
✔ 最佳答案
4. cos 4x = - 14x = arccos ( - 1) = 180, 540, 900, 1260
x = 180/4, 540/4, 900/4, 1260/4
= 45, 135, 225, 315,
5.
sin^2 2x = - 1/2
sin 2x = sqrt ( - 1/2) which is unreal, so no root.
6.
tan 2x = sqrt 3
2x = arctan ( sqrt 3) = 60, 240, 420, 600
x = 60/2, 240/2, 420/2, 600/2
= 30, 120, 210, 300.
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130605000051KK00013