Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
타원의 장축은 두 점을 연결하는 선입니다.taweonui jangchugeun du jeom-eul yeon-gyeolhaneun seonimnida.The major axis of the ellipse is the line connecting the two points.