What is the course title of the prerequisite of course Mobile Computing?
SELECT title FROM course WHERE course_id IN (SELECT T1.prereq_id FROM prereq AS T1 JOIN course AS T2 ON T1.course_id  =  T2.course_id WHERE T2.title  =  'Mobile Computing')
SELECT title FROM course WHERE course_id IN (SELECT T1.prereq_id FROM prereq AS T1 JOIN course AS T2 ON T1.course_id  =  T2.course_id WHERE T2.title  =  'Mobile Computing')
[{'title': 'Differential Equations'}, {'title': 'Sanitary Engineering'}]