Yellow flower

I am trying to identify this yellow flower. Any help would be appreciated.

 

Looks sort of like a Bidens.

 

Thank You. The only question I have is the number of petals. I have looked at some pictures of bidens and they only show 5 petals, this one has 8.

 

Those are not really petals. They are ray flowers, and Bidens can have more than 5.

 

Coreopsis?

 

helianthus divaricatus? The leaves are dissimilar on the bidens.

 

Showing leaves and plant habit would be better than just this view. Also at some point you may have to read descriptions rather than just look at pictures on the internet.

 

Thank you everyone!! This is not my flower but belongs to my sister in Nova Scotia, and just appeared in her garden. I have not seen it, just the picture she sent to me.