viewimage.php?no=24b0d769e1d32ca73dec85fa11d02831f032f3b7b65aa670697c5ec326227a12467da76538d196a2bc1191da455166c4e8988a52517f3339f9b8d30b639e76011a43c6c1cadd965f5f905af8ba664c9f14b28bb8a1b7

두 식이 같게 되는 이유가 뭐냐? u^2/c^2<<1이면 1이되야하는거 아님?