Lately your IPv6 network has experienced problems connecting new clients to the network.
As part of your troubleshooting, you run an ipconfig command on one of the client computers
and find two IPv6 addresses reported on the Ethernet interface: fe80::894d:c173:fef2 and
fdb9::75f8:e30c:7cf4. Which one indicates the DHCPv6 server is probably working correctly? How
do you know?

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)?