title: Polynomial Regression via LINEST
body: <p>I am trying to do a quadratic regression via LINEST in Excel 2013 as described in <a href="https://stackoverflow.com/questions/10857252/quadratic-and-cubic-regression-in-excel">this thread</a> with its wonderful answer. Unfortunately it does not work for me. What I get is the following:
  <img src="https://i.stack.imgur.com/wwsvS.gif" alt="Excel Sheet"></p>
  
  <p>I am using the German version of Excel, so I have to use the function <em>RGP</em> which is the equivalent of <em>LINEST</em>. And <em>WAHR</em> means <em>TRUE</em>.</p>
  
  <p>The cell in the 7th and 13th row just show the copied code from the arrays. Of course I get the same coefficients when I don't put <code>;;WAHR</code> at the end. I just want to show the entire stats to you, maybe it's important for the error diagnosis.</p>
  
  <p>When I try to get a cubic regression via <code>=RGP(B2:B5;A2:A5^{1,2,3})</code> Excel asks me if the formula should be corrected to <code>=RGP(B2:B5;A2:A5^{1,23})</code>. If I select <em>No</em>, I have to change the formula, because otherwise there would be a problem.</p>
  
  <p>So why do I not get 1, 2 and 1 as coefficients in the quadratic case and why does the cubic case not work at all? What could be the problem? Did anything change in Excel 2013?</p>