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Function: driver
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/libraries/Cacher.php
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Function: initiateCache
File: /volume1/web/PhpstormProjects/www_polymath_co_kr/application/controllers/ver3/Contents.php
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Function: get_footer
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Function: require_once
수학동아 - 폴리매스
함께 풀고 싶은 문제
창의력을 기를 수 있는 수학 문제 또는 퍼즐을 내는 곳입니다.
리프
2020.04.16 08:00
조회 811
전개도 위에 길이가 x인 곡선이 그려져 있다. 이때, 전개도를 접었을 때 곡선의 길이가 x로 유지됨을 증명하시오.
저도 정확한 증명은 모릅니다. 자명하다고 생각할 수도 있지만 수학적으로 이를 증명할 수 있지 않을까 해서 올려본 문제입니다. 곡선이 아닌 선분에 대해 증명하면 부분해결 드리겠습니다.
참고로 전개도는 다면체가 아닐 수도 있습니다. 예를 들어 원뿔이나 원기둥 같은 입체도형의 전개도에 대해서도 증명을 해야합니다.
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△π
Lv.9
2020.04.16 17:03
직관적으로는 자명한데 수학적 증명은 어렵네요ㅠㅠ
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원이 되면 안된다는 조건이 있어야 할 듯..
원은 전개도가 평면에서는 불가이므로..
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리프
Lv.7
2020.04.17 04:54
원이 된다는 게 무슨 뜻인지 이해가 안 되는데 좀 더 자세히 설명해주실 수 있나요?
좋아요0
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황금 열쇠
Lv.7
2020.04.17 17:49
제 생각에는 구가 전개도가 없으므로 구는 빼야된다는 뜻인 것 같은데요
좋아요0
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파스칼
Lv.7
2020.04.20 08:11
비밀댓글
비밀 댓글이 등록 되었습니다.
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리프
Lv.7
2020.04.21 07:19
좋아요0
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