title: Calculate the area of the parallelogram given two vectors in numpy
body: <p>Say I have two 3D vectors represented by two numpy arrays:</p>
  <pre><code>import numpy as np
  v1 = np.array([2, -3, 5])
  v2 = np.array([1, 4, -2])
  </code></pre>
  <p>I want to calculate the area of parallelogram, in which the two adjacent sides are given by <code>v1</code> and <code>v2</code>. I write the following code:</p>
  <pre><code>import math
  area = math.sqrt((v1[0] * v2[1] - v1[1] * v2[0])**2
                 + (v1[1] * v2[2] - v1[2] * v2[1])**2
                 + (v1[0] * v2[2] - v1[2] * v2[0])**2)
  
  print(area)
  # 19.949937343260004
  </code></pre>
  <p>The code is working fine, but what is the numpyic way to code this? I'm not familiar with numpy.</p>