Array ( [0] => Array ( [title] => L13A [link] => https://www.youtube.com/embed/pEne1ILXp9Q ) [1] => Array ( [title] => L13B [link] => https://www.youtube.com/embed/4twhViXx0YI ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - Lecture 13 | Center manifolds(proof