title: python math, numpy modules different results?
body: <p>I get slightly different results calculating the cosine of a value. How can I check that this difference is within machine precision?</p>
  
  <pre><code>import math
  math.cos(60.0/180.0*math.pi)
  -&gt; 0.5000000000000001
  
  import numpy
  numpy.cos(60.0/180.0*numpy.pi)
  -&gt; 0.50000000000000011
  </code></pre>