title: summation series using octave
body: <p>Is it possible to do a summation series in Octave?</p>
  
  <p>In <a href="https://stackoverflow.com/questions/12875692/summation-series-using-matlab">matlab</a> there is <code>symsum</code> function for it, however I didn't found anything similar for octave.</p>
  
  <p>For example, I want to find the following sum</p>
  
  <p><img src="https://i.stack.imgur.com/AeoEe.gif" alt="Summation"></p>
  
  <hr>
  
  <p>Addendum:</p>
  
  <p>Whether it's possible to sum something like this</p>
  
  <pre><code>f = @(x) nchoosek(5,x)*0.1.^x*0.9.^(5-x)
  
  sum(f([0:5]))
  </code></pre>
  
  <p>Failed with error</p>
  
  <pre><code>error: called from:
  error:   /usr/share/octave/3.6.4/m/help/print_usage.m at line 87, column 5
  error:   /usr/share/octave/3.6.4/m/specfun/nchoosek.m at line 95, column 5
  error:    at line -1, column -1
  error: evaluating argument list element number 1
  </code></pre>