\u6955\u5186\u306e\u5468\u306e\u9577\u3055<\/h3>\n
$\\displaystyle \\frac{x^2}{a^2} + \\frac{y^2}{b^2} = 1$ \u3067\u8868\u3055\u308c\u308b\u6955\u5186\u306e\u5468\u306e\u9577\u3055\u3002<\/p>\n
\u4fbf\u5b9c\u4e0a\uff0c$a > b > 0$ \u3068\u3057\u3066 $a$ \u3092\u9577\u534a\u5f84\uff0c$b$ \u3092\u77ed\u534a\u5f84\u3068\u547c\u3076\u3002\u96e2\u5fc3\u7387 $e$ \u3092\u4f7f\u3063\u3066\u66f8\u304f\u3068\uff0c<\/p>\n
\\begin{eqnarray}
\nb &=& a \\sqrt{1-e^2} \\\\
\n\\therefore\\ \\ e^2 &=& \\frac{a^2 – b^2}{a^2}
\n\\end{eqnarray}<\/p>\n
\u3053\u306e\u3068\u304d\uff0c\u6955\u5186\u306e\u5468\u306e\u9577\u3055 $L$ \u306f\uff0c<\/p>\n
$$ E(k) \\equiv \\int_0^{\\frac{\\pi}{2}} \\sqrt{1 -k^2 \\sin^2\\theta} \\,d\\theta $$<\/p>\n
\u3067\u5b9a\u7fa9\u3055\u308c\u308b\u7b2c\u4e8c\u7a2e\u5b8c\u5168\u6955\u5186\u7a4d\u5206<\/strong><\/span> $E(k)$ \u3092\u4f7f\u3063\u3066<\/p>\n $$L = 4 a E(e) = 4 a \\int_0^{\\frac{\\pi}{2}} \\sqrt{1 -e^2 \\sin^2\\theta} \\,d\\theta$$<\/p>\n \u3068\u66f8\u3051\u308b\u306e\u3067\u3042\u3063\u305f\u3002\u4ee5\u4e0b\u306e\u30da\u30fc\u30b8\u3092\u53c2\u7167\uff1a<\/p>\n
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