Array ( [0] => Array ( [title] => L31A [link] => https://www.youtube.com/embed/x2RVgVeUvvA ) [1] => Array ( [title] => L31B [link] => https://www.youtube.com/embed/FJ3o2OQvwck ) [2] => Array ( [title] => L31C [link] => https://www.youtube.com/embed/8KlVmPWKOf4 ) [3] => Array ( [title] => L31D [link] => https://www.youtube.com/embed/koGPUzpHVk8 ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第31R講 5.9 The Dirichlet and Abel tests