title: Python math domain error when using pow
body: <p>Here is the code:</p>
  
  <pre><code>exp = 1.79
  def calc(t):
      return pow(t - 1, exp)
  </code></pre>
  
  <p>The input values of <code>t</code> range from 0 to 1 (e.g. 0.04). This code throws a "math domain exception," but I'm not sure why. </p>
  
  <p>How can I solve this?</p>