BOOK(acc_no.,year,title)
USER(card_no.,names,address)
SUPPLIER(s_name,address)
BORROWED BY (acc_no.card_no,date of issue)
SUPPLIED BY(acc_no,date of supply,price ,s_name)
in above given relation find out the acc_no of all the book which are present in the library
in
(a)relational algebra form
(b) in sql form
(c)in tuple calculas form