{"id":7464,"date":"2007-03-05T15:09:00","date_gmt":"2007-03-05T15:09:00","guid":{"rendered":"http:\/\/melotopia.net\/b\/?p=7464"},"modified":"2007-03-05T15:09:00","modified_gmt":"2007-03-05T15:09:00","slug":"%ec%95%84%eb%ac%b4%ea%b2%83%eb%8f%84-%ec%97%86%eb%8a%94-%ea%b2%83%ec%9d%84-%eb%8a%98%ec%96%b4%eb%86%93%ea%b8%b0","status":"publish","type":"post","link":"http:\/\/melotopia.net\/b\/?p=7464","title":{"rendered":"\uc544\ubb34\uac83\ub3c4 \uc5c6\ub294 \uac83\uc744 \ub298\uc5b4\ub193\uae30"},"content":{"rendered":"<div class=\"desc\">\n        0!=1<\/p>\n<p>        !\uc740 factorial\uc774\ub77c\uace0 \ubd80\ub974\ub294\ub370, &#8220;\uacc4\uc2b9&#8221;\uc774\ub77c\uace0 \ud558\uae30\ub3c4 \ud55c\ub2e4.<br \/>\n        <sup class=\"footnote\"><br \/>\n<a href=\"#footnote_243_1\" id=\"footnote_link_243_1\" onmouseout=\"tistoryFootnote.hide(243,1)\" onmouseover=\"tistoryFootnote.show(this,243,1)\" style=\"color:#f9650d;font-family:Verdana,Sans-serif\"><br \/>\n<span style=\"display:none\"><br \/>\n           [\uac01\uc8fc:<br \/>\n          <\/span><br \/>\n          1<br \/>\n          <span style=\"display:none\"><br \/>\n           ]<br \/>\n          <\/span><br \/>\n<\/a><br \/>\n<\/sup><br \/>\n        \uc55e\uc5d0 \uc788\ub294 \uc22b\uc790\uac00 \uac00\ub839 n\uc774\ub77c\uba74, n!\uc740 n\ubd80\ud130 1\uae4c\uc9c0, 1\uc529 \ube7c\uac00\uba74\uc11c \ubaa8\ub450 \uacf1\ud55c \ud568\uc218\ub97c \ub73b\ud55c\ub2e4. \uc774 \ud568\uc218\ub294 n\uac00\uc9c0 \uc11c\ub85c \ub2e4\ub978 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\uc744 \ub54c \uac00\ub2a5\ud55c \uacbd\uc6b0\uc758 \uc218\ub97c \uacc4\uc0b0\ud560 \ub54c \uc0ac\uc6a9\ud55c\ub2e4. \uac00\ub839 4\uba85\uc774 \ud55c\uc904\ub85c \uc11c\ub294 \ubc29\ubc95\uc740 4*3*2*1=24\uac00\uc9c0\uc774\ub2e4. \uc989 4!=24\uc774\ub2e4.<br \/>\n        <br \/>\n        1!\uc740 1\uc774\ub2e4. 1\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc740 \uc624\uc9c1 1\uac00\uc9c0 \ubfd0\uc774\uae30 \ub54c\ubb38\uc774\ub2e4. \uadf8\ub7fc, 0!\uc740 \uc5b4\ub5bb\uac8c \ub420\uae4c?<br \/>\n        <br \/>\n        0!\uc774 1\uc778 \uc774\uc720\ub294 \ub2e4\uc74c\uacfc \uac19\uc774 \uc0dd\uac01\ud574\ubcfc \uc218 \uc788\ub2e4. n\uac1c\uc758 \uc11c\ub85c \ub2e4\ub978 \ubb3c\uac74\uc744 \ud55c\uc904\ub85c \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc758 \uac00\uc9d3\uc218\ub97c n!\uc774\ub77c\uace0 \ud560 \ub54c, 1!\uc740<br \/>\n1\uc778\uac83\uc774 \ud655\uc2e4\ud558\ub2e4. \uc0ac\uc2e4, n\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc5d0\uc11c n-1\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc740 \uc2e4\uc81c\ub85c \ubb3c\uac74\uc744 \ud55c\uac1c \ube7c\ubcf4\uba74 \ub418\ub294\ub370, \uc774\uac78 \uacc4\uc0b0\ud560\ub54c\ub294 n!\uc744 n\uc73c\ub85c \ub098\ub204\uba74 \ub41c\ub2e4. \ub9cc\uc57d 1\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc774 1\uac00\uc9c0\ub77c\uba74, 0\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\uc744 \uc218 \uc788\ub294 \ubc29\ubc95\uc740 1\uc744 1\ub85c  \ub098\ub204\uba74 \ub418\ubbc0\ub85c 0!=1\uc774 \ub41c\ub2e4.<br \/>\n        <sup class=\"footnote\"><br \/>\n<a href=\"#footnote_243_2\" id=\"footnote_link_243_2\" onmouseout=\"tistoryFootnote.hide(243,2)\" onmouseover=\"tistoryFootnote.show(this,243,2)\" style=\"color:#f9650d;font-family:Verdana,Sans-serif\"><br \/>\n<span style=\"display:none\"><br \/>\n           [\uac01\uc8fc:<br \/>\n          <\/span><br \/>\n          2<br \/>\n          <span style=\"display:none\"><br \/>\n           ]<br \/>\n          <\/span><br \/>\n<\/a><br \/>\n<\/sup><br \/>\n<br \/>\n<!-- END OF LOGGER TRACKING SCRIPT --><br \/>\n<!-- \uac8c\uc2dc\ud310\uc5d0 \ub300\ud55c \ud658\uacbd\uc124\uc815\uac12\uc744 \uc14b\ud305\ud558\uae30 \uc704\ud55c \ud398\uc774\uc9c0 -->\n<link href=\"include\/css.css\" rel=\"stylesheet\" type=\"text\/css\">\n<style>\n          P {margin-top:2px;margin-bottom:2px;}\n         <\/style>\n<p><script language=\"JavaScript\" type=\"text\/JavaScript\">\n          <!--\nfunction MM_swapImgRestore() { \/\/v3.0\n  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;\n}\n\nfunction MM_preloadImages() { \/\/v3.0\n  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();\n    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)\n    if (a[i].indexOf(\"#\")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}\n}\n\nfunction MM_findObj(n, d) { \/\/v4.01\n  var p,i,x;  if(!d) d=document; if((p=n.indexOf(\"?\"))>0&&parent.frames.length) {\n    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}\n  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];\n  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);\n  if(!x && d.getElementById) x=d.getElementById(n); return x;\n}\n\nfunction MM_openBrWindow(theURL,winName,features) { \/\/v2.0\n  window.open(theURL,winName,features);\n}\n\n\/\/-->\n         <\/script><br \/>\n<script language=\"JavaScript\" type=\"text\/JavaScript\">\n          <!--\nfunction fWriteMemo(){\n\t\n\t\tif (document.frmForm.content.value == \"\"){\n\t\t\talert(\"\uc758\uacac\uc744 \uc785\ub825 \ud558\uc138\uc694!!\");\n\t\t\tdocument.frmForm.content.focus();\n\t\t\treturn;\n\t\t}\n\t\tvar iCnt = 0;\n\t\tfor(i=0; i<document.frmForm.emoticon.length; i++){\n\t\t\tif (document.frmForm.emoticon[i].checked == true){\n\t\t\t\tiCnt = iCnt + 1;\n\t\t\t\tbreak;\n\t\t\t}\n\t\t}\n\t\tif (iCnt == 0){\n\t\t\talert(\"\uc774\ubaa8\ud2f0\ucf58\uc744 \uc120\ud0dd\ud574 \uc8fc\uc138\uc694!!\");\n\t\t\treturn;\n\t\t}\n\n\t\tdocument.frmForm.action=\"ah_memo_cr.asp\";\n\t\tdocument.frmForm.submit();\n\t}\n\n\tfunction fDeleteMemo(pMemoSeq) {\n\t\tans=confirm(\"\uc758\uacac\uc744 \uc0ad\uc81c\ud558\uc2dc\uaca0\uc2b5\ub2c8\uae4c?\");\n\t\tif(ans==true) {\n\t\t\tdocument.frmForm.MemoSeq.value = pMemoSeq;\n\t\t\tdocument.frmForm.action=\"ah_memo_rd.asp\";\n\t\t\tdocument.frmForm.submit();\n\t\t}\n\t}\n\n\tfunction checkEnter() {\n\t\tif (event.keyCode == 0xD) {\n\t\t\tfWriteMemo();\n\t\t\tevent.returnValue = false;\n\t\t}\n\t}\n\n\tfunction fDeleteBoardInfo() {\n\t\tans=confirm(\"\ud574\ub2f9\uae00\uc744 \uc0ad\uc81c\ud558\uc2dc\uaca0\uc2b5\ub2c8\uae4c?\");\n\t\tif(ans==true) {\n\t\t\tdocument.frmForm.action=\"ah_delete_rd.asp\";\n\t\t\tdocument.frmForm.submit();\n\t\t}\n\t}\n\t\n\t\/\/\uad00\ub9ac\uc790\ucd94\ucc9c\/\ucde8\uc18c\n\tfunction fAdminVote(pVoteYN){\n\t\tdocument.frmForm.votegb.value = \"ADMIN\";\n\t\tdocument.frmForm.voteyn.value = pVoteYN;\n\t\tdocument.frmForm.action = \"ah_vote_cr.asp\";\n\t\tdocument.frmForm.submit();\n\t}\n\n\t\/\/\uc0ac\uc6a9\uc790\ucd94\ucc9c\n\tfunction fUserVote(){\n\t\n\t\tdocument.frmForm.votegb.value = \"USER\";\n\t\tdocument.frmForm.action = \"ah_vote_cr.asp\";\n\t\tdocument.frmForm.submit();\n\t}\n\n\t\/\/\uac24\ub7ec\ub9ac\uac8c\uc2dc\ud310 \uad00\ub828\uc774\ubbf8\uc9c0 \n\tfunction fChangeImage(pName) {\n\t\tdocument.showimg.src = \"\/userdata\/commonboard\/screen\/1013\/\" + pName;\t\t\n\t}\n\n\t\/\/\uc0c1\uc138\uc774\ubbf8\uc9c0\ubcf4\uae30\n\tfunction fDetailImage(pFileNo) {\n\t\turl = \"ah_imageview_r.asp?idx=1013&no=2422&fno=\"+pFileNo;\n\t\twindow.open(url,\"\uc0c1\uc138\uc774\ubbf8\uc9c0\",\"toolbar=no,menubar=no,scrollbars=1,resizable=yes,width=500,height=400\");\n\t}\n\n\tfunction MM_swapImage() { \/\/v3.0\n\t  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)\n\t   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}\n\t}\n\t\n\tfunction fnNoAccess()\n\t{\n        alert('\ub85c\uadf8\uc778\uc744 \ud558\uc154\uc57c \ub429\ub2c8\ub2e4.');\n        return;\t\n\t}\n\t\n\t\n\/\/\ub124\ud2f0\ucf13 \uc2e0\uace0\uae00 \uc0c8\ucc3d\uc5d0 \ub728\uac8c \ud558\ub294 \ubd80\ubd84\n\n\n\/\/-->\n         <\/script><\/p>\n<div id=\"DivForHeight\" name=\"DivForHeight\">\n<form method=\"post\" name=\"frmForm\">\n<table align=\"center\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"600\">\n<tbody>\n<tr>\n<td align=\"middle\">\n<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"100%\">\n<tbody>\n<tr>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/form>\n<\/div>\n<p>\n         \ub530\ub77c\uc11c \uc74c\uc218\uc778 \uacbd\uc6b0\ub294, 0\uc73c\ub85c \ub098\ub204\ub294 \uacfc\uc815\uc774 \ud544\uc5f0\uc801\uc73c\ub85c \uac1c\uc785\ub418\ubbc0\ub85c \ubb34\ud55c\ub300\uac00 \ub098\uc628\ub2e4. \ud558\uc9c0\ub9cc Gamma\ud568\uc218\ub97c \uc774\uc6a9\ud558\uba74 \ubaa8\ub4e0 \uc591\uc758 \uc2e4\uc218\uc640 \uc815\uc218\uac00 \uc544\ub2cc \uc74c\uc758 \uc2e4\uc218\uc5d0 \ub300\ud574\uc11c \ud56d\uc0c1 \uacc4\uc0b0\ud560 \uc218 \uc788\uac8c \ub41c\ub2e4.<\/p>\n<div class=\"footnotes\">\n<ol class=\"footnotes\">\n<li id=\"footnote_243_1\">\n            \ub09c factorial\uc744 \ucc98\uc74c \ubc30\uc6b8\ub54c n!\uc774\ub77c\uace0 \uc368 \uc788\uc5b4\uc11c n\uc744 \uac15\ud558\uac8c \uc77d\uc5b4\uc57c\ud558\ub294\uc904 \uc54c\uc558\ub2e4. \ub098\uc911\uc5d0 \ub2e4\ub4e4 &#8220;n fac&#8221;\uc774\ub77c\uace0 \uc77d\ub354\ub77c.<br \/>\n            <a href=\"#footnote_link_243_1\"><br \/>\n             [\ubcf8\ubb38\uc73c\ub85c]<br \/>\n            <\/a>\n<\/li>\n<li id=\"footnote_243_2\">\n            \ubb3c\ub860 \uc218\ud559\uc801\uc73c\ub85c\ub294 Gamma\ud568\uc218\ub97c \uacc4\uc0b0\ud574\uc11c n=0\uc744 \ub300\uc785\ud558\uba74 \ub531 1\uc774 \ub098\uc624\uac8c \ub41c\ub2e4.<br \/>\n            <a href=\"#footnote_link_243_2\"><br \/>\n             [\ubcf8\ubb38\uc73c\ub85c]<br \/>\n            <\/a>\n<\/li>\n<\/ol>\n<\/div>\n<p><script type=\"text\/javascript\">\n          tistoryFootnote.add(243,1,\"\\ub09c factorial\\uc744 \\ucc98\\uc74c \\ubc30\\uc6b8\\ub54c n!\\uc774\\ub77c\\uace0 \\uc368 \\uc788\\uc5b4\\uc11c n\\uc744 \\uac15\\ud558\\uac8c \\uc77d\\uc5b4\\uc57c\\ud558\\ub294\\uc904 \\uc54c\\uc558\\ub2e4. \\ub098\\uc911\\uc5d0 \\ub2e4\\ub4e4 \\\"n fac\\\"\\uc774\\ub77c\\uace0 \\uc77d\\ub354\\ub77c.\");\ntistoryFootnote.add(243,2,\"\\ubb3c\\ub860 \\uc218\\ud559\\uc801\\uc73c\\ub85c\\ub294 Gamma\\ud568\\uc218\\ub97c \\uacc4\\uc0b0\\ud574\\uc11c n=0\\uc744 \\ub300\\uc785\\ud558\\uba74 \\ub531 1\\uc774 \\ub098\\uc624\\uac8c \\ub41c\\ub2e4. \");\n         <\/script><\/p>\n<div style=\"width:100%;margin-top:30px;clear:both;height:30px\">\n<div style=\"width:31px;float:left;\">\n<a href=\"\/toolbar\/popup\/abuseReport\/?entryId=243\" onclick=\"window.open(this.href, 'tistoryThisBlogPopup', 'width=550, height=510, toolbar=no, menubar=no, status=no, scrollbars=no'); return false;\"><br \/>\n<img data-recalc-dims=\"1\" decoding=\"async\" alt=\"\uc2e0\uace0\" src=\"https:\/\/i0.wp.com\/t1.daumcdn.net\/tistory_admin\/static\/ico\/ico_spam_report.png\" style=\"border:0\"\/><br \/>\n<\/a>\n<\/div>\n<\/div>\n<\/link>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>0!=1 !\uc740 factorial\uc774\ub77c\uace0 \ubd80\ub974\ub294\ub370, &#8220;\uacc4\uc2b9&#8221;\uc774\ub77c\uace0 \ud558\uae30\ub3c4 \ud55c\ub2e4. [\uac01\uc8fc: 1 ] \uc55e\uc5d0 \uc788\ub294 \uc22b\uc790\uac00 \uac00\ub839 n\uc774\ub77c\uba74, n!\uc740 n\ubd80\ud130 1\uae4c\uc9c0, 1\uc529 \ube7c\uac00\uba74\uc11c \ubaa8\ub450 \uacf1\ud55c \ud568\uc218\ub97c \ub73b\ud55c\ub2e4. \uc774 \ud568\uc218\ub294 n\uac00\uc9c0 \uc11c\ub85c \ub2e4\ub978 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\uc744 \ub54c \uac00\ub2a5\ud55c \uacbd\uc6b0\uc758 \uc218\ub97c \uacc4\uc0b0\ud560 \ub54c \uc0ac\uc6a9\ud55c\ub2e4. \uac00\ub839 4\uba85\uc774 \ud55c\uc904\ub85c \uc11c\ub294 \ubc29\ubc95\uc740 4*3*2*1=24\uac00\uc9c0\uc774\ub2e4. \uc989 4!=24\uc774\ub2e4. 1!\uc740 1\uc774\ub2e4. 1\uac1c\uc758 \ubb3c\uac74\uc744 \ub298\uc5b4\ub193\ub294 \ubc29\ubc95\uc740 \uc624\uc9c1 1\uac00\uc9c0 \ubfd0\uc774\uae30 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_crdt_document":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-7464","post","type-post","status-publish","format-standard","hentry","category-academic"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p8o6gA-1Wo","jetpack-related-posts":[],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=\/wp\/v2\/posts\/7464","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7464"}],"version-history":[{"count":0,"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=\/wp\/v2\/posts\/7464\/revisions"}],"wp:attachment":[{"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7464"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7464"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/melotopia.net\/b\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7464"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}