title: adding a column which derive from another column by an expression with awk
body: <p>How can I add a column after first, which has values calculate from an expression. this expression has a form: (vn+v0)*vl where v0 and vl is the first and last element of 3th column, respectively and vn is nth element of that column. for example we have a text table:</p>
  
  <pre><code>1 2 3 4
  10 20 30 40 
  100 200 300 400
  </code></pre>
  
  <p>it should be converted to </p>
  
  <pre><code>1  1800 3 4
  10  9900 30 40 
  100 180000 300 400
  </code></pre>
  
  <p>thanks</p>