|
ÊÁѤÃÊÁÒªÔ¡ | ¤ÙèÁ×Í¡ÒÃãªé | ÃÒª×èÍÊÁÒªÔ¡ | »¯Ô·Ô¹ | ¢éͤÇÒÁÇѹ¹Õé | ¤é¹ËÒ |
|
à¤Ã×èͧÁ×ͧ͢ËÑÇ¢éÍ | ¤é¹ËÒã¹ËÑÇ¢é͹Õé |
#1
|
||||
|
||||
¶ÒÁ⨷ÂìྪÃÂÍ´Á§¡Ø® Á.»ÅÒÂ
¼ÁÁÕ¢éÍʧÊÑ´ѧµèÍ仹Õé¤ÃѺ
$1. \binom{2003}{1}+ \binom{2003}{4}+ \binom{2003}{7}+...+ \binom{2003}{2002} $ ËÒ¤èÒÂѧ䧤ÃѺ ¾ÂÒÂÒÁáÅéÇáµè¤Ô´äÁèÍÍ¡¤ÃѺ 2. ÃкºÊÁ¡Òà $x+y+z = 0 $ $x^3+y^3+z^3 = 3$ $x^5+y^5+z^5 = 0$ ¨§ËÒ $ x^{2008}+y^{2008}+z^{2008}$ ËÒÂѧ䧤ÃѺ ¼ÁËÒä´éá¤è $ xyz =1 $ àͧ¤ÃѺ ¤Ô´äÁèÍÍ¡ÇèÒ¨ÐàÍÒ¡ÓÅѧ 5 ÁÒãªéÂÑ§ä§ ¢Íº¤Ø³ÁÒ¡¤ÃѺ
__________________
¤ÇÒÁ¾ÂÒÂÒÁá¡éäÁä´é·Ø¡àÃ×èͧ áµè 90%¢Í§ËÅÒÂæàÃ×èͧ¤ÇÒÁ¾ÂÒÂÒÁá¡éä´é |
#2
|
||||
|
||||
¢éÍ 1 ¡ÒÃá¡é»ÑËÒ·Õè¤ÅéÒ¡ѹ (à¤Ã´Ôµ¨Ò¡Ë¹Ñ§Ê×Í âÅ¡ÍÊÁ¡Òà 1 ¤ÃѺ)
|
#3
|
|||
|
|||
ÍéÒ§ÍÔ§:
¶éÒ $x+y+z=0$ áÅéÇ $\dfrac{x^5+y^5+z^5}{5}=\left(\dfrac{x^3+y^3+z^3}{3}\right)\left(\dfrac{x^2+y^2+z^2}{2}\right)$ ´Ñ§¹Ñé¹ $x^2+y^2+z^2=0$ ¨Ò¡àÍ¡Åѡɳì $(x+y+z)^2=x^2+y^2+z^2+2(xy+yz+zx)$ ¨Ðä´éÇèÒ $xy+yz+zx=0$ ¨Ö§ä´éÃкºÊÁ¡Òà $x+y+z=0$ $xy+yz+zx=0$ $xyz=1$ ´Ñ§¹Ñé¹ $x,y,z$ à»ç¹ÃÒ¡¢Í§ÊÁ¡Òà $t^3-1=0$ ¹Ñ蹤×Í $x^3=y^3=z^3=1$ ÅͧµèÍÍÕ¡¹Ô´¡çä´éáÅéǤÃѺ
__________________
site:mathcenter.net ¤Ó¤é¹ |
#4
|
||||
|
||||
#3
·èÒ¹ nooonuii ¤ÃѺ ¶éÒàÃҺ͡ÇèÒ⨷ÂìÁÕ¢éͺ¡¾Ãèͧ ÃкºÊÁ¡ÒÃäÁèà»ç¹¨ÃÔ§¨Ðä´éäËÁê¤ÃѺ à¾ÃÒÐã¹ÃдѺ Á.»ÅÒ ¶éÒäÁèä´é¡Ó˹´àÍ¡À¾ÊÑÁ¾Ñ·¸ì ¨Ð¶×ÍÇèÒàÍ¡À¾ÊÑÁ¾Ñ·¸ìà»ç¹à«µ¢Í§¨Ó¹Ç¹¨ÃÔ§ |
#5
|
||||
|
||||
ÁÒ¨Ò¡ä˹¤ÃѺ ËÃ×Íà»ç¹ÊÙµÃ˹Ö觷ÕèµéͧÃÙéàͧÍÂÙèáÅéǤÃѺ???
__________________
¤ÇÒÁ¾ÂÒÂÒÁá¡éäÁä´é·Ø¡àÃ×èͧ áµè 90%¢Í§ËÅÒÂæàÃ×èͧ¤ÇÒÁ¾ÂÒÂÒÁá¡éä´é 27 ¡Ñ¹ÂÒ¹ 2011 14:18 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ ÂѧËèÒ§ä¡Å¨Ò¡¤ÇÒÁà»ç¹à·¾ à˵ؼÅ: ⤷¼Ô´·Õè |
#6
|
||||
|
||||
»¡µÔ¶éÒÍÂÒ¡ËÒ¤èҢͧ $x^5+y^5+z^5$ ¨ÐàÃÔèÁ¨Ò¡¡ÒáÃШÒ $(x^3+y^3+z^3)(x^2+y^2+z^2)$ ¤ÃѺ (ÊÓËÃѺ¼Á¹Ð)
|
#7
|
|||
|
|||
à¼ÍÔÇèÒ¼Á¨ÓàÍ¡Åѡɳì¡ÓÅѧËéÒã¹ÃÙ»¹Ñé¹ä´éáÅéÇ¡çàÅÂà¢Õ¹ÍÍ¡ÁÒã¹ÃÙ»¹Ñé¹
áµè¶éÒÂѧäÁèÃÙé¨Ñ¡µÑǹÑé¹ãªéàÍ¡Åѡɳì¢Í§¹Ôǵѹ¡çä´é¤ÃѺ «Ö觤ÇèÐà»ç¹ÇÔ¸Õ¹Õéà¾ÃÒÐãªéä´é¡ÇéÒ§¡ÇèÒÁÒ¡ $x^n+y^n+z^n=(x+y+z)(x^{n-1}+y^{n-1}+z^{n-1})-(xy+yz+zx)(x^{n-2}+y^{n-2}+z^{n-2})+xyz(x^{n-3}+y^{n-3}+z^{n-3})$ $~~~~~~~~~~~~~~~~~=-(xy+yz+zx)(x^{n-2}+y^{n-2}+z^{n-2})+x^{n-3}+y^{n-3}+z^{n-3}$ $n=3$; $x^3+y^3+z^3=3$ $n=4$; $x^4+y^4+z^4=-(xy+yz+zx)(x^2+y^2+z^2)$ <-- äÁè¨Óà»ç¹µéͧËÒ¡çä´é $n=5$; $x^5+y^5+z^5=-(xy+yz+zx)(x^3+y^3+z^3)+x^2+y^2+z^2$ áµè $x^2+y^2+z^2=(x+y+z)^2-2(xy+yz+zx)=-2(xy+yz+zx)$ á·¹¡ÅѺä»ã¹¡Ã³Õ $n=5$ ä´é $0=-3(xy+yz+zx)-2(xy+yz+zx)$ $xy+yz+zx=0$
__________________
site:mathcenter.net ¤Ó¤é¹ |
#8
|
|||
|
|||
¶éÒ¼ÁÍÍ¡¢éÍÊͺ¢é͹Õé¨ÐãÊèà§×è͹ä¢ãËéÃÑ´¡ØÁ¡ÇèÒ¹Õé¤ÃѺ
__________________
site:mathcenter.net ¤Ó¤é¹ |
#9
|
||||
|
||||
#4
¶éÒ¼Á¨ÓäÁè¼Ô´ Á.»ÅÒÂäÁèä´éÁÕ¡ÒáÓ˹´ÇèÒàÍ¡À¾ÊÑÁ¾Ñ·¸ìµéͧà»ç¹¨Ó¹Ç¹¨ÃÔ§àËÁ×͹ Á.µé¹ ¡àÇé¹ã¹àÃ×èͧ૵·ÕèÁÕà¢Õ¹äÇéã¹ËÅÑ¡Êٵà à¾ÃÒÐ Á.»ÅÒÂÁÕàÃÕ¹àÃ×èͧ¨Ó¹Ç¹àªÔ§«é͹ ËÃ×ͺҧàÃ×èͧ·ÕèÁÕ¹ÔÂÒÁäÇé㹺·àÃÕ¹¤ÃѺ àªè¹ ¿Ñ§¡ìªÑè¹àÍ¡«ìâ»à¹ÅàªÕè¹ËÃ×Ϳѧ¡ìªÑè¹ÅÍ¡¡ÒÃÔ·ÖÁ à»ç¹µé¹ áÅТéÍÊͺÊèǹãËè·Õèãªéá¢è§¢Ñ¹ËÅÒ¤ÃÑ駡çäÁèä´éÃкØà¾Õ§áµèÇèÒ¨Ðä»ä´é¤ÓµÍºà»ç¹ÃٻẺä˹á¤è¹Ñé¹àͧ ¡ÑºÍÕ¡»ÃÐàÀ·¤×Í¡Ó˹´ÇèÒà»ç¹¨Ó¹Ç¹¨ÃÔ§äÇéã¹â¨·Âìà¾×è͵éͧ¡ÒÃãËéÃٻẺ¢Í§¤ÓµÍºÁÕ¤ÇÒÁà»ç¹ unique µÒÁ·Õè¼ÙéÍÍ¡¢éÍÊͺµéͧ¡Òà (à»ç¹¤ÇÒÁ¤Ô´àËç¹ÊèǹµÑǤÃѺ) #5 ÁÕ˹ѧÊ×Í ¾Õª¤³Ôµ ¢Í§ ÊÍǹ ÁÑé¤ÃѺ à»ç¹â¨·Âì»ÑËÒã¹Ë¹Ñ§Ê×ͤÃѺ |
#10
|
||||
|
||||
àÍ¡Åѡɳì¡ÓÅѧËéÒÍÕ¡Ãٻ˹Öè§ $(x+y+z)^5-x^5-y^5-z^5=5(x^2+y^2+z^2+xy+yz+zx)(x+y)(y+z)(z+x)$
¶éÒÁѹÂÒÇ¡ç¨ÓẺ¢Í§¾Õè Nooonuii ä»àÅ´աÇèÒ¤ÃѺ à¾ÃÒйÓä»»ÃÐÂØ¡µìä´é´Õ¡ÇèÒ â¨·Âì¢éÍ 1 Áѹ»ÃÐÂØ¡µì¨Ó¹Ç¹àªÔ§«é͹ ÅͧµÑ駢éÍÊѧࡵÇèÒÁѹËèÒ§¡Ñ¹ 3 ˹èÇ ¤×Í 1 4 7 ãªéÃÒ¡·Õè 3 ¢Í§ 1 ¶éÒËèÒ§¡Ñ¹ 6 ˹èÇ¡ç¹èÒ¨ÐãªéÃÒ¡·Õè 6 ¢Í§ 1 àªè¹»ÑËÒã¹ version ·ÕèÂÒ¡¢Ö鹤×Í ¨§ËÒ¤èҢͧ $\binom{n}{0}+\binom{n}{6}+\binom{n}{12}+...$
__________________
"ªÑèÇâÁ§Ë¹éÒµéͧ´Õ¡ÇèÒà´ÔÁ!" |
|
|