What will happen with communication methods in 10 years ?

Sally is editing her science report about living things. she needs to copy a paragraph from her original report. order the steps sally needs to do to copy the text to her new document.

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)?

Take a critical look at three gui applications you have used—for example, a spreadsheet, a word-processing program, and a game. describe how well each conforms to the gui design guidelines listed in this chapter.