Array ( [0] => Array ( [title] => L20A [link] => https://www.youtube.com/embed/IMZrexVfrZQ\ ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第20講|Lecture 3 Special Techniques|3_3D Separation of Variables 3_3_2 Spherical Coordinates Legendre Polynomials