add Korean Linear Algebra course link (#10944)

* add Korean Linear Algebra course link

add Korean Linear Algebra course link

* fix lint error

fix lint error (swap Alphabet ordering)

* fix lint error

fix lint error (alphabetical ordering)

courses/free-courses-ko.md

@@ -179,6 +179,7 @@
 
 ### Mathematics
 
+* [2013 2학기 선형대수](https://www.youtube.com/playlist?list=PLSN_PltQeOyjDGSghAf92VhdMBeaLZWR3) - (이상화 교수)
 * [수치해석](http://www.kocw.net/home/search/kemView.do?kemId=1297704) (국민대 김상철)
 * [수치해석 강의 동영상](https://youtube.com/playlist?list=PLczEhXyH_pUfKl9SPn-9j3K7olfBj5cpl) - 내가 이해한 기계공학 (WIU of Mech)
 * [전산수학1](http://www.kocw.net/home/search/kemView.do?kemId=1296081) (고려대 주재걸)