please only use relation algebra

question 4 Find the course id of all courses offered in Spring 2022.

Express each of the following queries in relational algebra - Be sure that the resulting relation lists just the attributes that are given in the instruction. - Do not include unnecessary relations in your queries. 7. Find the titles of all courses that have been taught in every semester/year. (5 points) 8. Rewrite your answer to problem 4 using only fundamental operations. (5 points) 9. Find the names of all instructors who have taught the same course more than once. (10