{"id":2044,"date":"2021-12-18T02:24:01","date_gmt":"2021-12-17T17:24:01","guid":{"rendered":"https:\/\/www.roundown.net\/nyushi\/?p=2044"},"modified":"2021-12-24T00:12:08","modified_gmt":"2021-12-23T15:12:08","slug":"tkb202103","status":"publish","type":"post","link":"https:\/\/www.roundown.net\/nyushi\/tkb202103\/","title":{"rendered":"\u6771\u5927\u6587\u7cfb2021\uff1a\u7b2c3\u554f"},"content":{"rendered":"
\n

\\(a , b\\) \u3092\u5b9f\u6570\u3068\u3059\u308b. \u5ea7\u6a19\u5e73\u9762\u4e0a\u306e\u653e\u7269\u7dda\r\n\\[\r\nC \\ : \\ y = x^2 +ax +b\r\n\\]\r\n\u306f\u653e\u7269\u7dda \\(y = -x^2\\) \u3068 \\(2\\) \u3064\u306e\u5171\u6709\u70b9\u3092\u6301\u3061, \u4e00\u65b9\u306e\u5171\u6709\u70b9\u306e \\(x\\) \u5ea7\u6a19\u306f \\(-1 \\lt x \\lt 0\\) \u3092\u6e80\u305f\u3057, \u4ed6\u65b9\u306e\u5171\u6709\u70b9\u306e \\(x\\) \u5ea7\u6a19\u306f \\(0 \\lt x \\lt -1\\) \u3092\u6e80\u305f\u3059.<\/p>\r\n

    \r\n

  1. (1)<\/strong>\u3000\u70b9 \\(( a , b )\\) \u306e\u3068\u308a\u3046\u308b\u7bc4\u56f2\u3092\u5ea7\u6a19\u5e73\u9762\u4e0a\u306b\u56f3\u793a\u305b\u3088.<\/p><\/li>\r\n

  2. (2)<\/strong>\u3000\u653e\u7269\u7dda \\(C\\) \u306e\u901a\u308a\u3046\u308b\u7bc4\u56f2\u3092\u5ea7\u6a19\u5e73\u9762\u4e0a\u306b\u56f3\u793a\u305b\u3088.<\/p><\/li>\r\n<\/ol>\r\n

    \r\n\r\n

    \u3010 \u89e3 \u7b54 \u3011<\/h4>\r\n

    (1)<\/strong><\/p>\r\n

    \\(2\\) \u3064\u306e\u653e\u7269\u7dda\u306e\u5f0f\u304b\u3089 \\(y\\) \u3092\u6d88\u53bb\u3059\u308b\u3068\r\n\\[\\begin{align}\r\nx^2 +ax +b & = -x^2 \\\\\r\n\\text{\u2234} \\quad 2x^2 +ax +b & = 0 \\quad ... [1]\r\n\\end{align}\\]\r\n[1] \u304c \\(-1 \\lt x \\lt 0\\) , \\(0 \\lt x \\lt 1\\) \u306b \\(1\\) \u3064\u305a\u3064\u89e3\u3092\u6301\u3064\u6761\u4ef6\u3092\u8003\u3048\u308c\u3070\u3088\u304f, \u305d\u308c\u306f\r\n\\[\r\nf(-1) \\gt 0 \\ \\text{\u304b\u3064} \\ f(0) \\lt 0 \\ \\text{\u304b\u3064} \\ f(1) \\gt 0\r\n\\]\r\n\u5404\u5f0f\u306b\u3064\u3044\u3066\r\n\\[\\begin{align}\r\nf(-1) & = -a +b +2 \\gt 0 \\\\\r\n& \\text{\u2234} \\quad b \\gt a-2 \\ , \\\\\r\nf(0) & = b \\lt 0 \\ , \\\\\r\nf(1) & = a +b +2 \\gt 0 \\\\\r\n& \\text{\u2234} \\quad b \\gt -a-2 \\\\\r\n\\end{align}\\]\r\n\u3088\u3063\u3066, \\(( a , b )\\) \u306e\u3068\u308a\u3046\u308b\u7bc4\u56f2\u306f\u4e0b\u56f3\u659c\u7dda\u90e8\uff08\u5883\u754c\u306f\u542b\u307e\u306a\u3044\uff09.<\/p>\r\n\"tkr20210101\"\r\n

    (2)<\/strong><\/p>\r\n

    \\(C\\) \u306e\u5f0f\u3088\u308a\r\n\\[\r\nb = -xa -x^2 +y\r\n\\]\r\n\u3053\u308c\u306f, \u50be\u304d \\(-x\\) \u306e\u76f4\u7dda\u3092\u8868\u3059.
    \r\n\\(b = g(a)\\) \u3068\u304a\u3044\u3066, \u3053\u306e\u76f4\u7dda\u304c (1)<\/strong> \u3067\u6c42\u3081\u305f\u9818\u57df\u3068\u5171\u6709\u70b9\u3092\u3082\u3064\u6761\u4ef6\u3092\u8003\u3048\u308c\u3070\u3088\u304f, \u305d\u308c\u306f\u4ee5\u4e0b\u306e\u3044\u305a\u308c\u304b\u3067\u3042\u308b.<\/p>\r\n

      \r\n

    1. 1*<\/strong>\u3000\\(g(-2) g(2) \\lt 0\\) \u3059\u306a\u308f\u3061\r\n\\[\r\n( y -x^2 +2x ) ( y -x^2 -2x ) \\lt 0\r\n\\]<\/li>\r\n

    2. 2*<\/strong>\u3000\u300c \\(g(-2) \\lt 0\\) \u304b\u3064 \\(g(2) \\lt 0\\) \u304b\u3064 \\(g(0) \\gt -2\\) \u300d\u3059\u306a\u308f\u3061\r\n\\[\r\ny \\lt x^2 +2x \\ \\text{\u304b\u3064} \\ y \\lt x^2 -2x \\ \\text{\u304b\u3064} \\ y \\gt x^2 -2\r\n\\]<\/li>\r\n<\/ol>\r\n

      \u3088\u3063\u3066, \\(C\\) \u306e\u901a\u308a\u3046\u308b\u9818\u57df\u306f\u4e0b\u56f3\u659c\u7dda\u90e8\uff08\u5883\u754c\u306f\u542b\u307e\u306a\u3044\uff09.<\/p>\r\n\"tkr20210102\"\r\n","protected":false},"excerpt":{"rendered":"\\(a , b\\) \u3092\u5b9f\u6570\u3068\u3059\u308b. \u5ea7\u6a19\u5e73\u9762\u4e0a\u306e\u653e\u7269\u7dda \\[ C \\ : \\ y = x^2 +ax +b \\] \u306f\u653e\u7269\u7dda \\(y = -x^2\\) \u3068 \\(2\\) \u3064\u306e\u5171\u6709\u70b9\u3092\u6301\u3061, \u4e00\u65b9\u306e\u5171\u6709\u70b9\u306e \\(x\\) \u5ea7\u6a19\u306f … \u7d9a\u304d\u3092\u8aad\u3080 →<\/span><\/a>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[180],"tags":[149,165],"class_list":["post-2044","post","type-post","status-publish","format-standard","hentry","category-tokyo_b_2021","tag-tokyo_b","tag-165"],"_links":{"self":[{"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/posts\/2044","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/comments?post=2044"}],"version-history":[{"count":0,"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/posts\/2044\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/media?parent=2044"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/categories?post=2044"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.roundown.net\/nyushi\/wp-json\/wp\/v2\/tags?post=2044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}