RELATIONAL ALGEBRA HELP THANKS

Running Example: Schema Diagram for University Database 2. (6 points) Write the following queries in relational algebra, using the university schema I gave you in class. a. Find the ids and names of all the students who have taken at least one Comp. Sci. course. b. Find the ids and names of all students who have not taken any courses before 2019. c. Find the ids of students who have received an "A" on all the courses they have taken