This question was correctly answered by someone and then the OP deleted it.

Is $xy y' = \sqrt{y^2 + 1}$ separable or non-separable?

Is there some rule against this?

It makes it appear that they are cheating on HW or something.

Also, for the person who answered it, is that really fair?

  • 5
    $\begingroup$ Hey, you're right! This happens from time to time. If you notice, you can flag a mod and we'll undelete it if we think the deletion is in bad faith. I've undeleted this question (not because I was the answerer --- I would have generally). And yes, it is unfair to the person who answered it. I might also mention that this doesn't come up if the answer is upvoted, as the OP cannot delete their own question if there are upvoted answers. $\endgroup$
    – davidlowryduda Mod
    Apr 17 '16 at 23:45
  • 3
    $\begingroup$ Ah, further, this user has done this before to other users. Good catch. $\endgroup$
    – davidlowryduda Mod
    Apr 17 '16 at 23:46
  • 2
    $\begingroup$ It is one reason to be generous in quickly up-voting an otherwise unloved only Answer on an on-topic Question, as this prevents the "bilking" behavior, taking the benefit of an Answer without contributing that content to other Readers. $\endgroup$
    – hardmath
    Apr 18 '16 at 0:30
  • 4
    $\begingroup$ Related: Why do some users delete their questions after receiving an answer? $\endgroup$ Apr 18 '16 at 3:53

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