title: Numpy / Pandas optimized vector operations
body: <p>Suppose I had a dataframe df:</p>
  
  <pre><code>  Vx    Vy
  0 1.00  1.00
  1 2.00  3.00
  2 1.50  1.75 
  </code></pre>
  
  <p>The goal is to create a new column <code>df['Vmagnitude']</code> defined as the magnitude of the vector sum between Vx and Vy, like <a href="https://i.stack.imgur.com/NAXey.png" rel="nofollow noreferrer">in this picture</a>:</p>
  
  <pre><code>  Vx    Vy    Vmagnitude
  0 1.00  1.00  1.41421
  1 2.00  3.00  3.60555
  2 1.50  1.75  2.30489
  </code></pre>
  
  <p>What would be the fastest and/or most pythonic way of implementing this using numpy/pandas?</p>