title: why doesn't this ReplaceAll work in mathematica
body: <p>I have </p>
  
  <pre><code>Table[{x1, 1, 2, 3}^i, {i, 0, 3}] /. x1 -&gt; 1/2
  </code></pre>
  
  <p>But the following does not work, since x1 is not replaced with 1/2</p>
  
  <pre><code>Table[{x1, 1, 2, 3}^i, {i, 0, 3}] // Inverse /. x1 -&gt; 1/2
  </code></pre>
  
  <p>Could anybody let me know why and how to fix it? Many thanks!</p>