{"id":2095,"date":"2025-12-24T17:18:41","date_gmt":"2025-12-24T08:18:41","guid":{"rendered":"https:\/\/math-travel.com\/?p=2095"},"modified":"2026-02-11T16:26:59","modified_gmt":"2026-02-11T07:26:59","slug":"sincoskousiki","status":"publish","type":"post","link":"https:\/\/math-travel.jp\/math-1\/sincoskousiki\/","title":{"rendered":"\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3092\u4f7f\u3044\u3053\u306a\u305d\u3046\uff013\u3064\u306e\u91cd\u8981\u516c\u5f0f\u3068\u8a08\u7b97\u3092\u30b9\u30d4\u30fc\u30c9\u30a2\u30c3\u30d7\u3055\u305b\u308b\u30b3\u30c4"},"content":{"rendered":"\n
\u6570\u5b66\u2160\u4e09\u89d2\u6bd4\u306e\u306a\u304b\u3067\u3082\u300c\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u300d\u306f\u304b\u306a\u308a\u91cd\u8981\u306a\u516c\u5f0f<\/span>\u3067\u3059\u3002<\/span><\/p>\n\n\n\n \u300c\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3063\u3066\u306a\u3093\u3060\u3063\u3051\uff1f\u300d <\/p>\n\n\n\n \u300c\u3069\u3046\u3084\u3063\u3066\u4f7f\u3046\u3093\u3060\u3063\u3051\uff1f\u300d<\/p>\n<\/div><\/div>\n\n\n \u4e09\u89d2\u6bd4\u304c\u3068\u3063\u3066\u3082\u82e6\u624b\u3067\u3059\u2026<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n \u672c\u8a18\u4e8b\u3067\u306f\u3001\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2<\/span>\u306b\u3064\u3044\u3066\u307e\u3068\u3081\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n \u4e09\u89d2\u6bd4\u306e\u5358\u5143\u306b\u306f\u91cd\u8981\u516c\u5f0f\u304c\u591a\u304f\u3042\u308a\u307e\u3059\u304c\u3001\u305d\u306e\u4e2d\u3067\u3082\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u306f\u5fc5\u305a\u899a\u3048\u3066\u6b32\u3057\u3044\u516c\u5f0f<\/span>\u3067\u3059\u3002<\/p>\n\n\n\n \\(\\sin^{2} \\theta+\\cos^{2} \\theta = 1\\) \u3053\u306e\u76f8\u4e92\u95a2\u4fc2\u306f\u6570\u2161\u306e\u300c\u4e09\u89d2\u95a2\u6570\u300d\u3067\u3082\u4f7f\u3046\u306e\u3067\u3001\u3053\u306e\u6a5f\u4f1a\u306b\u5fc5\u305a\u899a\u3048\u307e\u3057\u3087\u3046\u3002<\/span><\/p>\n\n\n \u3067\u3082\u899a\u3048\u3065\u3089\u3044\u3057,\u4f7f\u3044\u65b9\u3082\u3088\u304f\u5206\u304b\u3089\u306a\u3044\u3067\u3059\u2026<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n \u3068\u306f\u3044\u3048\u3001\u521d\u3081\u306f\u4f7f\u3044\u65b9\u3082\u3088\u304f\u5206\u304b\u3089\u306a\u3044\u3067\u3059\u3088\u306d\u3002\u307c\u304f\u3082\u5b8c\u74a7\u306b\u899a\u3048\u3089\u308c\u308b\u307e\u3067\u306f\u4f55\u5ea6\u3082\u8abf\u3079\u3066\u307e\u3057\u305f<\/p>\n\n\n\n \u672c\u8a18\u4e8b\u3067\u306f\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3092\u4e01\u5be7\u306b\u89e3\u8aac\u3057\u3066\u3044\u308b<\/span>\u306e\u3067\u305c\u3072\u6700\u5f8c\u307e\u3067\u3054\u89a7\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n \u6c17\u306b\u306a\u308b\u898b\u51fa\u3057\u3092\u30af\u30ea\u30c3\u30af\u3057\u3066\u3001 \u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u306f\u5fc5\u305a\u62bc\u3055\u3048\u3066\u304a\u304d\u305f\u3044\u91cd\u8981\u306a\u516c\u5f0f<\/span>\u3067\u3059\u3002<\/span><\/p>\n\n\n\n \\(\\sin^{2} \\theta+\\cos^{2} \\theta=1\\) \u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3092\u4f7f\u3046\u30e1\u30ea\u30c3\u30c8\u3068\u3057\u3066\u306f\u3001sin,cos,tan\u306e\u3069\u308c\u304b1\u3064\u304c\u5206\u304b\u308c\u3070\u4ed6\u306e\u5168\u3066\u3092\u6c42\u3081\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3053\u3068\u3067\u3059\u3002<\/span><\/p>\n\n\n \u3048\uff011\u3064\u5206\u304b\u308c\u3070\u5168\u90e8\u5206\u304b\u308b\u306e!?<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n \u3068\u3066\u3082\u4fbf\u5229\u3060\u304b\u3089\u5fc5\u305a\u899a\u3048\u3088\u3046\uff01<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n \u305d\u308c\u3067\u306f\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u306e\u4f7f\u3044\u65b9\u306b\u3064\u3044\u3066\u89e3\u8aac\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n \uff13\u3064\u306e\u516c\u5f0f\u304c\u5927\u4e8b\u306a\u306e\u306f\u5206\u304b\u3063\u305f\u3051\u3069\u3001\u3069\u3046\u3084\u3063\u3066\u4f7f\u3046\u306e\uff1f<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n \u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3092\u4f7f\u3063\u3066\u5b9f\u969b\u306b\u5404\u5024\u3092\u6c42\u3081\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n \u4e0b\u90e8\u306b\u4f8b\u984c3\u3064\u3092\u7528\u610f\u3057\u305f\u306e\u3067\u305d\u308c\u305e\u308c\u306e\u4f7f\u3044\u65b9\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n \u3053\u306e\u516c\u5f0f\u306f\u3001\\(\\sin \\theta\\)\u3082\u3057\u304f\u306f\\(\\cos \\theta\\)\u304c\u5206\u304b\u308b\u3068\u304d\u306b\u4f7f\u3046\u516c\u5f0f\u3067\u3059\u3002<\/p>\n\n\n\n \u4f8b\u3048\u3070\\(\\theta\\)\u304c\u92ed\u89d2\u3067\\(\\displaystyle \\sin \\theta=\\frac{1}{3}\\)\u3060\u3068\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n \u3053\u306e\u3068\u304d\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u2460\u3092\u7528\u3044\u3066\u3001<\/p>\n\n\n\n \\[\\sin^{2} \\theta+\\cos^{2} \\theta=1\\]<\/p>\n\n\n\n \\[\\displaystyle (\\frac{1}{3})^{2}+\\cos^{2} \\theta=1\\]<\/p>\n\n\n\n \\[\\displaystyle \\frac{1}{9}+\\cos^{2} \\theta=1\\]<\/p>\n\n\n\n \\[\\displaystyle \\cos^{2} \\theta=\\frac{8}{9}\\]<\/p>\n\n\n\n \u3053\u306e\u3088\u3046\u306b\\(\\cos\\)\u306e\u5f0f\u306b\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3057\u305f\u3002<\/p>\n\n\n\n \u3053\u3053\u3067\u3001\\(\\cos \\theta\\)\u3092\u6c42\u3081\u308b\u969b\u306b\u7b26\u53f7\u306e\u6b63\u8ca0<\/span>\u306b\u6c17\u3092\u4ed8\u3051\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n \u4eca\u56de\u306f\\(\\theta\\)\u304c\u92ed\u89d2\u306a\u306e\u3067\u3001\\(\\cos \\theta > 0\\)<\/p>\n\n\n\n \\[\\displaystyle \\cos \\theta=\\frac{2\\sqrt{2}}{3}\\]<\/p>\n\n\n\n \\(\\sin \\theta\\)\u3082\u3057\u304f\u306f\\(\\cos \\theta\\)\u304c\u5206\u304b\u308b\u3068\u304d\u306f\u76f8\u4e92\u95a2\u4fc2\u2460\u3092\u7528\u3044\u308b\u3053\u3068\u3067\u3001\u3082\u3046\u4e00\u65b9\u3082\u6c42\u3081\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n \u76f8\u4e92\u95a2\u4fc2\u2460\u306e\u516c\u5f0f\u3067\\(\\sin \\theta,\\cos \\theta\\)\u3092\u6c42\u3081\u305f\u5f8c\u306b\\(\\tan \\theta\\)\u3092\u6c42\u3081\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n \\(\\displaystyle \\sin \\theta=\\frac{1}{3}\\),\\(\\displaystyle \\cos \\theta=\\frac{2\\sqrt{2}}{3}\\)\u306e\u3068\u304d\u3001<\/p>\n\n\n\n \\begin{eqnarray} \u9006\u306b\\(\\tan \\theta\\)\u3068\\(\\sin \\theta\\)\u304c\u5206\u304b\u3063\u3066\u3044\u3066\u3001\\(\\cos \\theta\\)\u3092\u6c42\u3081\u308b\u30d1\u30bf\u30fc\u30f3\u3082\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n \u516c\u5f0f\u3092\u6697\u8a18\u3059\u308b\u3060\u3051\u3067\u306a\u304f\u3001\u5f0f\u3092\u5909\u5f62\u3057\u3066\u4f7f\u3044\u3053\u306a\u305b\u308b\u3088\u3046\u306b\u6163\u308c\u3066\u3044\u304d\u307e\u3057\u3087\u3046\uff01<\/p>\n\n\n\n \u3053\u306e\u516c\u5f0f\u306f\\(\\tan \\theta\\)\u3082\u3057\u304f\u306f\\(\\cos \\theta\\)\u304c\u5206\u304b\u308b\u6642\u306b\u4f7f\u3046\u516c\u5f0f\u3067\u3059\u3002<\/p>\n\n\n\n \\(\\theta\\)\u304c\u92ed\u89d2\u3067\u3001\\(\\displaystyle \\tan \\theta=\\frac{\\sqrt{2}}{4}\\)\u306e\u3068\u304d\u3001<\/p>\n\n\n\n \\begin{eqnarray} \\(\\theta\\)\u304c\u92ed\u89d2\u306a\u306e\u3067\u3001\\(\\cos \\theta >0\\)<\/p>\n\n\n\n \\[\\displaystyle \\cos \\theta = \\frac{2\\sqrt{2}}{3}\\]<\/p>\n\n\n\n \u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u304c\u306a\u305c\u6210\u308a\u7acb\u3064\u306e\u304b\u3001\u305d\u308c\u305e\u308c\u306e\u5f0f\u3092\u8a3c\u660e\u3057\u3066\u304a\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n
\u9ad8\u6821\u751f<\/span><\/div>
\\(\\displaystyle \\tan \\theta = \\frac{\\sin \\theta}{\\cos \\theta}\\)
\\(\\displaystyle 1+\\tan ^{2} \\theta = \\frac{1}{\\cos ^{2} \\theta}\\)<\/p>\n<\/div><\/div>\n\n\n\n
\u9ad8\u6821\u751f<\/span><\/div>
\u30b7\u30fc\u30bf<\/span><\/div>
\u305c\u3072\u6700\u5f8c\u307e\u3067\u3054\u89a7\u304f\u3060\u3055\u3044\u3002<\/p>\n<\/span><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2<\/h2>\n\n\n\n
\\(\\displaystyle \\tan \\theta=\\frac{\\sin \\theta}{\\cos \\theta}\\)
\\(\\displaystyle 1+\\tan ^{2} \\theta=\\frac{1}{\\cos ^{2} \\theta}\\)<\/p>\n<\/div><\/div>\n\n\n\n
\u9ad8\u6821\u751f<\/span><\/div>
\u30b7\u30fc\u30bf<\/span><\/div>\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3000\u4f7f\u3044\u65b9<\/h2>\n\n\n
\u9ad8\u6821\u751f<\/span><\/div>\\(\\sin^{2} \\theta+\\cos^{2} \\theta=1\\)<\/h3>\n\n\n\n
\\(\\displaystyle \\tan \\theta=\\frac{\\sin \\theta}{\\cos \\theta}\\)<\/h3>\n\n\n\n
\\displaystyle \\tan \\theta &=& \\frac{\\sin \\theta}{\\cos \\theta}\\\\
\\displaystyle &=& \\frac{\\frac{1}{3}}{\\frac{2\\sqrt{2}}{3}}\\\\
\\displaystyle &=& \\frac{1}{3} \u00d7 \\frac{3}{2\\sqrt{2}}\\\\
\\displaystyle &=& \\frac{1}{2\\sqrt{2}}\\\\
\\displaystyle &=& \\frac{\\sqrt{2}}{4}
\\end{eqnarray}<\/p>\n\n\n\n\\(\\displaystyle 1+\\tan ^{2} \\theta=\\frac{1}{\\cos ^{2} \\theta}\\)<\/h3>\n\n\n\n
\\displaystyle 1+\\tan ^{2} \\theta &=& \\frac{1}{\\cos ^{2} \\theta}\\\\
\\displaystyle 1+\\frac{2}{16} &=& \\frac{1}{\\cos ^{2} \\theta}\\\\
\\displaystyle \\frac{9}{8} &=& \\frac{1}{\\cos ^{2} \\theta}\\\\
\\displaystyle \\cos ^{2} \\theta &=& \\frac{8}{9}
\\end{eqnarray}<\/p>\n\n\n\n\u4e09\u89d2\u6bd4\u306e\u76f8\u4e92\u95a2\u4fc2\u3000\u8a3c\u660e<\/h2>\n\n\n\n