title: how to delete third element in a list using scheme
body: <p>This is what I want:</p>
  
  <pre><code>(delete-third1 '(3 7 5))    ==&gt;  (3 7)
  (delete-third1 '(a b c d))  ==&gt;  (a b d)
  </code></pre>
  
  <p>so I did something like:</p>
  
  <pre><code>(define (delete-third1 LS ) (list(cdr LS)))
  </code></pre>
  
  <p>which returns </p>
  
  <pre><code>(delete-third1 '(3 7 5))
  ((7 5))
  </code></pre>
  
  <p>when it should be <code>(3 7)</code>. What am I doing wrong?</p>