Specify the following queries in relational algebra on the database schema given in Exercise 5.15: a. Give the details (all attributes of trip relation) for trips that exceeded $2,000 in expenses. Book_id Title Publisher_name BOOK BOOK_COPIES Book_id Branch_id No_of_copies BOOK_AUTHORS Book_id Author_name LIBRARY_BRANCH Branch_id Branch_name Address PUBLISHER Name Address Phone BOOK_LOANS Book_id Branch_id Card_no Date_out Due_date BORROWER Card_no Name Address Phone Figure 8.14 A relational database schema for a LIBRARY database. 284 Chapter 8 The Relational Algebra and Relational Calculus b. Print the Ssns of salespeople who took trips to Honolulu. c. Print the total trip expenses incurred by the salesperson with SSN = ‘234-56-7890’