title: divide pandas dataframe elements by its line max
body: <p>I wonder how to divide the elements in DataFrame by its line max. See following code:</p>
  
  <pre><code>index = pd.date_range('1/1/2000', periods=8)
  df = DataFrame(np.random.randn(8, 3), index=index, columns=['A', 'B', 'C'])
  dfMax = df.max(axis=1)
  </code></pre>
  
  <p>and then, the elements in df will be dividedby dfMax based on the same line. Does anyone have an idea?</p>