In Rational rose, what does the <<extend>> usecase mean.?

Question

Pls give some eg., it says tat <> relationship specifies optional functionality. If a person can perform 3 jobs (say, add,del,edit) can i give <> relationship from the Actor to the 3 Usecases??

Answer 1

we use an extend relationship to specify that one use case (extension) extends the behavior of another use case (base). This type of relationship reveals details about a system or application that are typically hidden in a use case.

there is no extend relation b/w actor and usecases...
Extend/Include/Inherit relationship exists among usecases...

extend means that the use case being extended may or may not use the extending use case (which is more likely to be used by other use cases or exist as an independent process).

'Turn' is use case....Turn left and Turn right are its Extended usecases...

do read the URLs in source... very helpful :)