According to the diagram, write the following queries using relational algebra.

Please make sure the answers are expressed as Relational Algebra, (Handwritten preference)

takes ID sec il student /D dept ame tot cned section course department advisor litle dept name credits building budget time slot day end time ilding time_slot id prere instructor dept ame ipacity eaches Figure 2.8 Schema diagram for the university database. Express answers in relational algebra. Your queries should NOT include unneeded relations Write three queries - one using only cross products, one using only theta joins, and one using only natural joins - to find the names of all students who received an A in the course with the title Database Design. (10 points) Find the ID's of all instructors who have taught or are teaching a course from a different department than the one to which they are assigned. For example, the result would include Electrical Engineering professors who teach Computer Science courses. (10 points) Find the names of all instructors who have taught the same course more than once. (10 points)