How to represent a use case contains another on UML?

I'm modeling my web project using UML, I got a case that's neither <<includes>> nor <<extends>> it's in which a case contains another, How can I represent it? I have use case called "Project manager" and another calle开发者_运维技巧d "Tasks manager", as you can notice, managing tasks is a subset of project management, so how do I represent that in UML?

Thanks for your answers in advance! Regards!

First Use Cases are requiremens.

So  who are your actors?( Who use your system?)
And what are your use cases? (What they do with your system)

"Project manager"- "Tasks manager" does not seems to right use cases. They seem to software entities or part of GUI.

So try to figure out "who will use" Project managager?(what ever it is). And what will the user do with that? ( suppose See Project Team Members, Create New Task.... Assign Task).

Do not worry. Your use case can cross between different parts of actual software. So ,realization of Create New Task use case can involve many parts of real software.

For use case point it is not important. They are requirements not software design abstractions.

Probably you should use Inclusion relationship.

You should improve your understanding of use cases, maybe by some more reading. What you actually describe might as well be an <<include>> dependency, because if you in an use cases invoke scenarios of another use cases, it means you included one use case into another.