Re: [考古] 中正94 曲率

看板trans_math作者pobm (待從頭收拾舊河山)時間18年前 (2007/06/16 12:28)推噓5(5推 0噓 12→)

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※ 引述《ahongyeh (小葉子)》之銘言： : Let r(t) = f(t)i + g(t)j be a smooth curve defined by twice-differentiable : function x = f(t) and y = g(t). : (a) Show that the curvature κ of the curve is given by the formula : │f'g" - g'f"│ : κ = ──────────── : ┌ 2 2 ┐(3/2) : │(f') + (g') │ : └ ┘ 這一小題阿 |r'(t) X r''(t)| 你用κ= ------------------ |r'(t)|^3 很快的 : (b) Let r be the ellipse r(t) = acosti + bsintj with a>b>0. : Show that r has its largest curvature on its major axis : and its smallest curvature on its minor axis. 這一小題拿上題結果微一下就好也滿快的不過說實話這張不是很簡單的我覺得這題一定要會阿~~ 其實中正的題目我覺得還滿有水準的XD : 問老師... : 他只丟了一句話... : 考出來就送給他了... : 考出來就送給他了... : 考出來就送給他了... : 考出來就送給他了... : 有人會這題嗎!? -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 125.226.173.220

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HUJIKOLP

06/16 12:29, , 1^F

06/16 12:29, 1^F

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HUJIKOLP

06/16 12:30, , 2^F

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pobm

06/16 12:31, , 3^F

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