In a relational database, the three basic operations used to develop useful sets of data are:

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Write the pseudo code for this problem based on what you learned from the video. the purpose is to design a modular program that asks the user to enter a distance in kilometers, and then converts that distance to miles. the conversion formula is as follows: miles = kilometers x 0.6214

Technician a says that a new replacement part is always good. technician b says that sometimes recent repair work will be the cause of a complaint. who is correct? a. both technicians a and b b. technician a c. technician b d. neither technician a nor b