평속으로 풀려니깐 미지수범벅에 2차식도 나오는데 맞음?
간단한 풀이 있을까요
https://gall.dcinside.com/mgallery/board/view/?id=physics2&no=647403&page=1
https://gall.dcinside.com/mgallery/board/view/?id=physics2&no=647403&page=1