take a course (in something)
To enroll in, attend, and work toward the completion of an academic course (in some topic). I took a course in the evenings to learn how to speak Japanese. She's taking a course in macroeconomics that sounds really interesting.
take a course (in something)
to enroll in a course and do the required work. I decided to take a course in history. Bob drives into the city where he is taking a course.