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ãËé X1 X2 X3 X4 X5 X6 ¤×ÍÃÒ¡·Õèà»ç¹¨Ó¹Ç¹àªÔ§«é͹·Ñé§ËÁ´¢Í§ X^6+X^5+...+X+1=0 ¨§ËÒ¤èÒ 1/X1-1 +1/X2-1 +...+1/X6-1
Âѧ䧪èÇÂ͸ԺÒÂãËé´éǹЧѺ¢Íº¤Ø§§Ñº 14 ¡ØÁÀҾѹ¸ì 2008 21:18 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ nongtum |
#2
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à»ç¹ $\frac{1}{x_{1} - 1}$ ËÃ×Í $\frac{1}{x_{1}} - 1$ ¤ÃѺ.
¶éÒµÒÁ·Õèà¢Õ¹ÁÒ ¢é͵¡Å§¢Í§ªÒÇâÅ¡ àÃҨзӡÒÃËÒáè͹ź ´Ñ§¹Ñé¹ ¤§ËÁÒ¶֧ ẺËÅѧ $\frac{1}{x_{1}} - 1$ ´Ñ§¹Ñé¹·Õèµéͧ¡Òä×Í $(\frac{1}{x_{1}} + ... + \frac{1}{x_{6}}) - 6$ ÊÁÁµÔãËé $y = \frac{1}{x} $ á·¹ã¹ÊÁ¡ÒèÐä´é $y^6 + y^5 + ... + y + 1 = 0$ ´Ñ§¹Ñé¹ $\frac{1}{x_{1}} + ... + \frac{1}{x_{6}} = y_{1} + ... + y_{6} = -1$ (ÊÑÁ»ÃÐÊÔ·¸Ôì¢Í§ $y^5$) ´Ñ§¹Ñ鹵ͺ -7 ¤ÃѺ.
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The Lost Emic <<-- ˹ѧÊ×Íà©Å¢éÍÊͺÃдѺ»ÃжÁ¹Ò¹ÒªÒµÔ EMIC ¤ÃÑ駷Õè 1 - ¤ÃÑ駷Õè 8 ªØ´ÊØ´·éÒ ËŧÁÒ 15 ¡ØÁÀҾѹ¸ì 2008 00:00 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ gon |
#3
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¢Íº¤Ø§§Ñº ¢Íº¤Ø³ÁÒ¡æ¤ÃѺ
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#4
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¶éÒà»ç¹áººááµÍº $-3$ ¤ÃѺ
ÃÒ¡¢Í§¾ËعÒÁ´Ñ§¡ÅèÒǨÐÍÂÙèã¹ÃÙ» $a,b,c,\overline{a},\overline{b},\overline{c}$ ¨Ò¡¹Ñé¹¾Ô¨ÒóҼźǡ·ÕÅФÙè $$\frac{1}{a-1}+\frac{1}{\overline{a}-1}=\frac{a+\overline{a}-2}{a\cdot\overline{a}-a-\overline{a}+1}=\frac{a+\overline{a}-2}{2-a-\overline{a}}=-1$$
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site:mathcenter.net ¤Ó¤é¹ |
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