Array ( [0] => Array ( [title] => L16A [link] => https://www.youtube.com/embed/jrGURI_m4RI ) [1] => Array ( [title] => L16B [link] => https://www.youtube.com/embed/JVD5qML_Mik ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第16講 The First Fundamental Form and the Area of a Surface (cont.)