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กำหนดให้ |
z |
= |
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เมื่อ |
r |
= |
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และให้ |
zk |
= |
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จะได้ว่า |
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= |
z |
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= |
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นั่นคือ |
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= |
r |
|
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rk |
= |
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และ |
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= |
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= |
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จาก (1) และ (2) จะได้ |
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= |
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เมื่อ |
k |
= |
0, 1, 2, 3, ..., (n - 1) |
|
กำหนดให้ |
z |
= |
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|
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เมื่อ |
r |
= |
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และให้ zk เป็นรากที่ n ของ z |
|
จะได้ |
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= |
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|
เมื่อ |
k |
= |
0, 1, 2, 3, ..., (n - 1) |
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|
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จาก |
z |
= |
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= |
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= |
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จากสูตร |
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= |
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จะได้ |
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= |
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= |
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= |
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= |
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= |
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= |
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= |
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= |
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= |
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ดังนั้น รากที่ 3 ของ z ได้แก่ |
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