Section 6.9 of your textbook ("Debugging") lists three possibilities to consider if a function is not working. Describe each possibility in your own words.

Define "precondition" and "post-condition" as part of your description.

Create your own example of each possibility in Python code. List the code for each example, along with sample output from trying to run it.

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)?

What can a word user do with the customize ribbon dialog box? check all that apply. minimize the ribbon add a new tab to the ribbon remove a group from a tab add a group to a tab choose which styles appear choose which fonts appear choose tools to appear in a group

In the insert table dialog box, you select the checkbox to create the first row as the header of the table.