![Use case diagrams are UML diagrams describing units of useful functionality (use cases) performed by a system in collaboration with external users (actors). Use case diagrams are UML diagrams describing units of useful functionality (use cases) performed by a system in collaboration with external users (actors).](https://www.uml-diagrams.org/use-case-diagrams/business-use-case-diagram-elements.png)
Use case diagrams are UML diagrams describing units of useful functionality (use cases) performed by a system in collaboration with external users (actors).
![Use Case Diagram, UML Diagrams Example: Website (structuring use cases with extend and include use case) - Visual Paradigm Community Circle Use Case Diagram, UML Diagrams Example: Website (structuring use cases with extend and include use case) - Visual Paradigm Community Circle](https://circle.visual-paradigm.com/wp-content/uploads/2017/08/Use-Case-Diagram-Website-_-Structuring-use-cases-with-extend-and-include-use-case-2.png)
Use Case Diagram, UML Diagrams Example: Website (structuring use cases with extend and include use case) - Visual Paradigm Community Circle
What is the difference between extend and include functions in a use case diagram and their uses? - Quora
![Comparing and Contrasting Use Case Model Elements, Part 1 - Business Analyst Articles, Webinars, Templates, Jobs Comparing and Contrasting Use Case Model Elements, Part 1 - Business Analyst Articles, Webinars, Templates, Jobs](https://www.batimes.com/wp-content/uploads/2021/05/vangalen_Img01_Nov5.png)
Comparing and Contrasting Use Case Model Elements, Part 1 - Business Analyst Articles, Webinars, Templates, Jobs
![Comparing and Contrasting Use Case Model Elements, Part 1 - Business Analyst Articles, Webinars, Templates, Jobs Comparing and Contrasting Use Case Model Elements, Part 1 - Business Analyst Articles, Webinars, Templates, Jobs](https://www.batimes.com/wp-content/uploads/2021/05/vangalen_Img05_Nov5.png)