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#1
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¶ÒÁàÃ×èͧ¡ÒÃËÒÃŧµÑÇ
àªè¹ Áըӹǹ¹Ñº¡Õè¨Ó¹Ç¹·ÕèÁÕ¤èÒÃÐËÇèÒ§ $100$ ¡Ñº $1000$ áÅÐËÒôéÇ $7$ ŧµÑÇ áÅéÇàÃÒÁÒãªéÊÙµÃ
$n=\frac{a_n-a_1}{7}+1$ àÁ×èÍ n ¤×ͨӹǹ·Õè $7$ ËÒÃŧµÑÇ·Ñé§ËÁ´ áÅÐ $a_1$ ¤×ͨӹǹáá·Õè $7$ ËÒÃŧµÑÇ $a_n$ ¤×Í ¨Ó¹Ç¹ÊØ´·éÒ·Õè $7$ ËÒÃŧµÑÇ ÊÙµÃÁÕ·ÕèÁÒÂÑ§ä§ ËÒÇÔ¸ÕÍ×è¹ä´éÁÑé ÁÕº·¾ÔÊÙ¨¹ìÁÑé¤ÃѺ |
#2
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à»ç¹¤ÇÒÁÃÙéàÃ×èͧÅӴѺàÅ¢¤³Ôµ à¾ÃÒШӹǹ·ÕèËÒôéÇ $7$ ŧµÑǨÐà»ç¹ÅӴѺàÅ¢¤³Ôµ·ÕèÁռŵèÒ§ÃèÇÁà·èҡѺ $7$
¢é͹Õé¼ÁãªéÊٵà $\left[\dfrac{999}{7}\right]-\left[\dfrac{100}{7}\right]$ «Öè§ÁÒ¨Ò¡ $\spadesuit$ ¨Ó¹Ç¹¢Í§¨Ó¹Ç¹¹ÑºµÑé§áµè $1$ ¶Ö§ $n$ ·ÕèËÒôéÇ $k$ ŧµÑÇÁÕÍÂÙè·Ñé§ËÁ´ $\left[\dfrac{n}{k}\right]$ ¨Ó¹Ç¹ ¾ÔÊÙ¨¹ì à¢Õ¹ $n=kq+r$ àÁ×èÍ $0\leq r<k$ ¨Ðä´éÇèÒ ¨Ó¹Ç¹¹ÑºµÑé§áµè $1$ ¶Ö§ $n$ ·ÕèËÒôéÇ $k$ ŧµÑÇ ¤×Í $k,2k,...,qk$ «Öè§ÁÕ $q$ ¨Ó¹Ç¹ áµè $q\leq q+\dfrac{r}{k} $ $~= \dfrac{n}{k}$ $~<q+1$ ¨Ö§ä´é $\left[\dfrac{n}{k}\right] =q$
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site:mathcenter.net ¤Ó¤é¹ |
#3
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function floor 1000/7-floor 100/7 = 142-14=128
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äÁèÍÂÒ¡ãËé·Ø¡¤¹à¤ÃÕ´¡Ñ¹à¡Ô¹ä»¹Ð¤ÃѺ 1.äÍá«¡¹ÔǵÑé¹ÃÙéÍÐäÃàÁ×èÍáÍ»à»Ôŵ¡Å§ÁÒÂѧ·Õè æ à©Å ÃÙéÇèÒà¢Ò¤ÇÃ仹Ñ觷ÕèÍ×è¹ 2.ÊÁÁµÔÇèҤسà»ç¹à¨éҢͧÃéÒ¹ÍÒËÒÃÃéҹ˹Ö觷Ñé§ÃéÒ¹ÁÕâµêÐÍÒËÒà 4 âµêÐ ..âµêÐ˹Öè§ âµêÐÊͧà¾Ôè§ÊÑè§ÍÒËÒÃâµêÐÊÒÁ¨èÒÂà§Ô¹ààÅéÇáµèâµêÐÊÕèàºÕéÂÇ ¤Ø³¨Ð·ÓÍÂèÒ§äà à©Å ¨Ñ´ãËéµÃ§ 3.຤áÎÁâ´¹ãºá´§áÅéÇä»ä˹ à©Å ä»à»ç¹·ËÒà |
#4
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ãªéÇÔ¸Õ¡ÒùѺµÑÇ index
µÑÇ·ÕèËÒôéÇ 7 ŧµÑǨÐÍÂÙèã¹ÃÙ» 7k àÁ×èÍ k à»ç¹¨Ó¹Ç¹àµçÁ áÅÐ µÑÇáá·Õè·ÕèÍÂÙèÃÐËÇèÒ§ 100 -1000 ¤×Í 7x(100/7 »Ñ´¢Öé¹ à¾×èÍãËéÁѹÁÒ¡¡ÇèÒ 100) = 7(15) áÅеÑÇÊØ´·éÒ¤×Í 7x(100/7 »Ñ´Å§à¾×èÍãËéÁѹäÁèà¡Ô¹ 1000)= 7(142) ´Ñ§¹Ñé¹µÑÇàÅ¢·ÕèËÒÃà¨ç´Å§µÑÇÃÐËÇèÒ§ 100-1000 à·èҡѺ¨Ó¹Ç¹µÑÇàÅ¢ 15 ¶Ö§ 142 «Öè§ÁÕ·Ñé§ËÁ´ 142-15+1 =... |
#5
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¶éÒäÁèÍÂÒ¡¨ÓÊÙµÃÍÒ¨ÊѧࡵÍÂèÒ§¹Õé¡çä´é¤ÃѺ
¨Ó¹Ç¹ÃÐËÇèÒ§ $100$ ¶Ö§ $1000$ ·ÕèËÒôéÇ $7$ ŧµÑÇ à¢Õ¹à»ç¹ÅӴѺä´é´Ñ§¹Õé $$105,112,119,...,994$$ $$7(15),7(16),7(17),...,7(142)$$ àÃҨйѺ¨Ó¹Ç¹¢Í§µÑÇàÅ¢·Ñé§ËÁ´ â´Â¡ÒÃÊѧࡵµÑÇàÅ¢ã¹Ç§àÅçº ä´éÇèÒ ¨Ò¡ $1$ ¶Ö§ $14$ ÁÕ $14$ ¨Ó¹Ç¹ áÅÐ ¨Ò¡ $1$ ¶Ö§ $142$ ÁÕ $142$ ¨Ó¹Ç¹ ¹Ñ蹤×Í ¨Ò¡ $15$ ¶Ö§ $142$ ¨ÐÁÕ·Ñé§ËÁ´ $142-14=128$ ¨Ó¹Ç¹ |
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