Whats a drone cause i have no idea

Singing in the rain: this first part of the film shows the early history of motion picture. how accurate do you think the portrayal of the early motion picture industry is? why? is historical accuracy important in films and theater productions? explain.

How do we use the sumif formula (when dealing with different formats) ?

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)?