Array ( [0] => Array ( [title] => L2AR [link] => https://www.youtube.com/embed/4MQhoCVrhfI ) [1] => Array ( [title] => L2BR [link] => https://www.youtube.com/embed/lpi6pKoGEdk ) [2] => Array ( [title] => L2CR [link] => https://www.youtube.com/embed/AGoW9zJIOQQ ) [3] => Array ( [title] => L2DR [link] => https://www.youtube.com/embed/kbe3Wx8GPdg ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第2R講 2.1, 2.2 極限、左極限和右極限