Array ( [0] => Array ( [title] => L2A [link] => https://www.youtube.com/embed/E2piGb_g4kk ) [1] => Array ( [title] => L2B [link] => https://www.youtube.com/embed/OS_hadS8ifM ) [2] => Array ( [title] => L2C [link] => https://www.youtube.com/embed/sstyq2--unc ) [3] => Array ( [title] => L2D [link] => https://www.youtube.com/embed/yCPU82pkQv4 ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第2R講 6.4 Conditions for differentiability