title: Creating a matrix from a column and a row
body: <p>What is the most elegant way to multiply a column and a row together to make a matrix.</p>
  <p>I want to take two series and make a dataframe from them with the length of one series and the width of another.
  In this case I want to multiply the two.</p>
  <pre><code>sr1 = 
  0     2
  1     3     
  2     4
  
  sr2 = 
  0         0
  1        10
  2        100
  3        50
  </code></pre>
  <p>Desired result: a dataframe where sr1 = y axis, sr2 = x axis</p>
  <pre><code>0   20   200   100
  0   30   300   150
  0   40   400   200
  </code></pre>
  <p>Is there a simple function in pandas or something similar that does this without first repeating a series as columns in a df and then multiplying?</p>