"write down a loop invariant to prove the correctness of this program, and briefly explain why the invariant is correct"

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)?

How would you categorize the software that runs on mobile devices? break down these apps into at least three basic categories and give an example of each.

Donnie does not have powerpoint. which method would be best for elana to save and share her presentation as is? a pdf a doc an rtf a ppt