title: Gaussian function python
body: <p>I'm trying to plot the Gaussian function using matplotlib.
  This is my code:</p>
  
  <pre><code>    #!/usr/bin/env python
      from matplotlib import pyplot as plt
      import numpy as np
      import math
  
      def gaussian(x, alpha, r):
            return 1./(math.sqrt(alpha**math.pi))*np.exp(-alpha*np.power((x - r), 2.))
  
      x = np.linspace(-3, 3, 100)
      plt.plot(gaussian(x, 1, 0))
  
      plt.show()
  </code></pre>
  
  <p>Why the range is from 0 to 100 instead of being between -3 and 3?<a href="https://i.stack.imgur.com/NaJgu.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NaJgu.png" alt="enter image description here"></a></p>