# What happened to the interesting question about $L_1$ approximation of $x^n$?

Earlier this morning, there was an interesting question on this site about finding the closest approximation to $x^n$ by lower degree polynomials, in the $L^1$ norm on $[0,1]$.

I've figured out how to make Mathematica compute the answers almost immediately, and I'm seeing some interesting patterns in the answers, but I can't find the question anymore!

If the original user deleted this in response to the claim that this was in standard textbooks on approximation theory, then I will say that I don't think this is a good reason to delete it. I scanned through some online lecture notes on approximation theory before I started thinking about it, and I could only find the $L_2$ and $L_{\infty}$, not the $L_1$, cases. If experts know where to find this in textbooks, then let them post an explanation of this, but it isn't obvious to me.

• For 10k+ users: the question is here. I cast a vote to undelete the question because I am interested in seeing answers to this, too.
– t.b.
Jan 9 '12 at 15:43
• A meta-comment: Moderators can search for deleted questions. However, this would work the best if you can provide some keywords in the original title of the question. I just tried searching for "approximate" and "approximation" and didn't find any that matched your description. It is a good thing that @t.b. remembered it, since questions deleted by the original owner are not listed in the 10K Tools. Jan 9 '12 at 15:48
• The question is now undeleted.
– t.b.
Jan 9 '12 at 16:44