\u3042\u308b\u6570\u5b66\u306e\u6559\u80b2\u8005\u304c\u9f3b\u9ad8\u3005\u306b\u8a00\u3046\u3002
\n\u300c\u79c1\u306f\u3001x^3=8 \u306e\u5b9f\u6570\u89e3\u3092\u6c42\u3081\u308b\u5fc5\u8981\u304c\u89e3\u7b54\u306e\u4e2d\u3067\u73fe\u308c\u305f\u3068\u304d\u306f\u3001\u5fc5\u305a\u3001
\nx^3-8=0
\n(x-2)(x^2+2x+4)=0
\n\u3068\u3057\u3066\u30012\u6b21\u65b9\u7a0b\u5f0f x^2+2x+4=0 \u306b\u3064\u3044\u3066\u306b\u3082\u89e6\u308c\u3066\u304a\u304f\u3053\u3068\u306b\u3057\u3066\u3044\u308b\u3002\u3059\u306a\u308f\u3061, 2 \u6b21\u65b9\u7a0b\u5f0f\u306e\u5224\u5225\u5f0f\u3092 D \u3068\u304a\u304f\u3068\u3001
\nD\/4 =1-4=-3<0
\n\u3067\u3042\u308b\u304b\u3089\u3053\u306e 2 \u6b21\u65b9\u7a0b\u5f0f\u306f\u5b9f\u6570\u89e3\u3092\u3082\u305f\u306a\u3044\u3053\u3068\u306b\u3064\u3044\u3066\u89e6\u308c\u3001\u305d\u306e\u5f8c\u3067 x^3=8 \u306e\u5b9f\u6570\u89e3\u306f x=2 \u3060\u3051\u3067\u3042\u308b\u3002
\n\u3068\u3059\u308b\u3002\u300d
\n\u3053\u306e\u3088\u3046\u306b\u8a00\u3046\u3002\u305d\u308c\u3067\u81ea\u5206\u306e\u6388\u696d\u306f\u4e01\u5be7\u306a\u3093\u3060\u3068\u3044\u3046\u3002\u3053\u308c\u306f\u3001x^3=8 \u306e\u5b9f\u6570\u89e3\u304c x=2 \u3060\u3051\u3067\u3042\u308b\u3068\u3044\u3046\u306e\u306f\u81ea\u660e\u3067\u306f\u306a\u3044\u3068\u3044\u3046\u7acb\u5834\u3067\u3042\u308b\u3002<\/p>\n
\u3057\u304b\u3057\u3001\u4f55\u304b\u304a\u304b\u3057\u304f\u306f\u306a\u3044\u304b? \u306a\u305c\u306a\u3089 3 \u4e57\u6839 a \u306e\u8a18\u53f7\u306f\u3001\u5b9f\u6570 a \u306b\u3064\u3044\u3066\u306f\u3001x^3=a \u3068\u306a\u308b x \u306f\u300c\u305f\u3060\u4e00\u3064\u5b58\u5728\u300d\u3057\u3001\u305d\u308c\u3092\u30003 \u4e57\u6839\u3068\u3088\u3076\u3068\u3044\u3046\u3053\u3068\u306f\u8a8d\u3081\u3066\u3044\u308b\u3067\u306f\u306a\u3044\u304b\u3002\u3059\u306a\u308f\u3061 3 \u4e57\u6839\u306e\u8a18\u53f7\u3092\u4f7f\u3063\u3066\u3044\u308b\u3068\u3044\u3046\u3053\u3068\u306f\u3001x^3=a \u3092\u6e80\u305f\u3059 x \u306f\u4e00\u3064\u3057\u304b\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u3092\u3059\u3067\u306b\u8a8d\u3081\u3066\u3044\u308b\u3067\u306f\u306a\u3044\u304b\u3002<\/p>\n
\u3053\u308c\u4ee5\u5916\u306b\u3082\u3001\u500b\u4eba\u7684\u306b\u306f\u3001\u6570\u5b66 III \u3067 x>sin x \u3067\u3042\u308b\u3053\u3068\u3092\u793a\u305b\u3068\u3044\u308f\u308c\u305f\u3068\u304d\u306b\u3001f(x)=x-sin x \u3068\u304a\u3044\u3066 f(x) \u3092\u5fae\u5206\u3059\u308b\u306e\u306f\u3084\u3081\u3066\u3082\u3089\u3044\u305f\u3044\u3068\u601d\u3046\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u3042\u308b\u6570\u5b66\u306e\u6559\u80b2\u8005\u304c\u9f3b\u9ad8\u3005\u306b\u8a00\u3046\u3002 \u300c\u79c1\u306f\u3001x^3=8 \u306e\u5b9f\u6570\u89e3\u3092\u6c42\u3081\u308b\u5fc5\u8981\u304c\u89e3\u7b54\u306e\u4e2d\u3067\u73fe\u308c\u305f\u3068\u304d\u306f\u3001\u5fc5\u305a\u3001 x^3-8=0 (x-2)(x^2+2x+4)=0 \u3068\u3057\u3066\u30012\u6b21\u65b9\u7a0b\u5f0f x^2+2x+4=0 \u306b\u3064\u3044\u3066\u306b\u3082\u89e6\u308c\u3066 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-20","post","type-post","status-publish","format-standard","hentry","category-4"],"_links":{"self":[{"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=20"}],"version-history":[{"count":4,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/20\/revisions"}],"predecessor-version":[{"id":23,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=\/wp\/v2\/posts\/20\/revisions\/23"}],"wp:attachment":[{"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/math.co.jp\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}