Quote (IHateDuriel @ Jan 30 2016 06:54am)
]The correct form would be: Wouldn't you ?
Therefore not ending with a contraction.
There's nothing incorrect about "You wouldn't?". You don't always need to use inversion for questions. You can keep the same structure as a declarative especially for emphasizing disbelieve or a rhetorical question as opposed to being literally interrogative.
And you can still end a sentence with a contraction in other constructions.
I would end a sentence in a contraction sometimes, but you say that you wouldn't.
Quote (IHateDuriel @ Jan 30 2016 06:54am)
As stated before, you should not use contraction in a formal paper.
That's true.