$1.$ Define the term $$functional requirement$.$

$2.$ What are the three perspectives on functional requirements? Explain

each perspective in ONE sentence.

$3.$ For each of these perspectives, describe an example requirement that

may arise in the development of an online shop.

$4.$ Extract the requirements from the project description below. If

necessary, expand the requirements to avoid insufficient requirements

engineering.

$$The client must be able to connect to the server without any

problems. The precondition is that the server has already been booted

and must have its own IP$.$ Then the client can connect to the server.

The connection between client and server must work smoothly after

half of the project duration. The client should offer the possibility to

add friends permanently.

Once two clients are connected to the same server at the same time, it

must be possible to send messages between clients. The use of the

client should be kept simple so that the user can use the client without

much effort. Furthermore, the client should run on most common

operating systems and be easy to install