title: Generating the coefficients of a Chebyshev polynomial in Python
body: <p>I am trying to compute the coefficients of the <em>k<sup>th</sup></em> Chebyshev polynomial. Let's just set <em>k</em> to 5 for this. So far, I have the following:</p>
  
  <pre><code>a = (0,0,0,0,0,1) #selects the 5th Chebyshev polynomial
  p = numpy.polynomial.chebyshev.Chebyshev(a) #type here is Chebyshev
  cpoly = numpy.polynomial.chebyshev.cheb2poly(p) #trying to convert to Poly
  print cpoly.all_coeffs()
  </code></pre>
  
  <p>After the second line runs, I have an object of type <code>Chebyshev</code>, as expected. However, the third line fails to convert to a type <code>Poly</code>, and converts to type <code>numpy.ndarray</code>. Thus, I get an error saying that ndarray has no attribute <code>all_coeffs</code>. </p>
  
  <p>Anyone know how to fix this?</p>