This [Question](http://math.stackexchange.com/questions/1093774/trouble-doing-simple-polynomial-interpolation) got closed as a duplicate of another by the same user, [namely this](http://math.stackexchange.com/questions/1093771/trouble-doing-polynomial-interpolation), but it is the former that has an Answer.  (The former was migrated to Math.SE as the new user had cross-posted the same problem.)

I recommend the closed-as-duplicate status be switched to the unanswered version, and have voted to reopen accordingly (so the other/unanswered one can be closed instead).