Uml use case diagram <<extend>>

Question

I am little bit confused in use of <<extend>> . Can you check my diagram?
https://www.sololearn.com/post/1751383/?ref=app

Answer 1

Yes, I think your diagram makes sense.
"Extends" means that a certain activity is optional and part of another use case.
In this context, viewing the recipes is the main activity, and optionally the user can give a like and write a comment, when he/she is logged in.