Let l(n) be the number of ways to tile a 2 × n rectangle with l-shaped tiles of area 3 (trominoes). write a recurrence for l(n). java

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 is html ? give a small description about html

Brian wants to conduct an online search with a certain phrase. he intends to use the words books that belong to the 1800s in his search. how should he use the word that in his search?