> **Undeleted**

I would like [this question](http://math.stackexchange.com/questions/1162751/how-do-i-differentiate-sin1-x) to be undeleted. It was voluntarily removed by the author although a correct answer was given. Given the [OP](http://math.stackexchange.com/users/26643/dotman14)'s history on MSE, it seems the user asks questions, gets answers, and then deletes the questions. I do not think this should be permitted, as some user in the future may have the same question as the OP, but a valid answer will not be present due to a senseless deletion.