Array ( [0] => Array ( [title] => L21A [link] => https://www.youtube.com/embed/SN6w-VijZBI ) [1] => Array ( [title] => L21B [link] => https://www.youtube.com/embed/SN6w-VijZBI ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第21R講 Eigenvalues and Eigenvectors IV