title: SyntaxError when using $
body: <p>I'm learning Python via Jupyter Notebook.
  I'd like to calculate x̄ from a set of data, then print out the value in a string. 
  How do I get the variable x̄?</p>
  
  <p>I've tried using $\bar x$  and $\overline {x}$   but both return a Syntax Error</p>
  
  <p>Am I missing a library?
  I have </p>
  
  <pre><code>from matplotlib import pyplot as plt
  import numpy as np
  </code></pre>
  
  <pre><code>f = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
  print($\bar x$ + f" = {np.average(f)}")
  
    File "&lt;ipython-input-128-0e2d9b6ee635&gt;", line 2
      print($\bar x$ + f" = {np.average(f)}")
            ^
  SyntaxError: invalid syntax
  </code></pre>
  
  <pre><code>f = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
  print($\overline {x}$ + f" = {np.average(f)}")
  
    File "&lt;ipython-input-129-2807d1e5e7ae&gt;", line 2
      print($\overline {x}$ + f" = {np.average(f)}")
            ^
  SyntaxError: invalid syntax
  </code></pre>