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
파선은 원의 경로를 따라 그려진 곡선입니다.Paseon-eun won-ui gyeonglo-reul ttala geureojin goksun-imnida.A cycloid is a curve traced by a point on the circumference of a circle as it rolls along a straight line.