cos 3x=cosx
(用general solution 表示,清楚列明步驟,唔該)
緊急....maths.. General solution
2009-04-30 6:13 am
回答 (2)
2009-04-30 6:18 am
✔ 最佳答案
cos 3x=cosxcos3x-cosx=0
-2sin2xsinx=0
sin2xsinx=0
sin2x=0 or sinx=0
2x=180n x=180n
x=90n
a.maths method...=.=
參考: me
2009-04-30 7:45 am
cos3x = cosx
3x = 360ºn + x or 3x = 360º - x
2x = 360ºn or 4x = 360ºn
x = 180ºn or x = 90ºn
Ans: x = 90ºn
3x = 360ºn + x or 3x = 360º - x
2x = 360ºn or 4x = 360ºn
x = 180ºn or x = 90ºn
Ans: x = 90ºn
收錄日期: 2021-04-13 16:35:31
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