title: How to display a graph in ipython notebook
body: <p>Trying to do some plotting in SymPy -</p>
  
  <p>As per <a href="https://youtu.be/cvHyaE_bs8s?t=1028" rel="noreferrer">this video</a> I have written :</p>
  
  <pre><code>from sympy.plotting import plot, plot_parametric
  
  e = sin(2*sin(x**3))
  plot(e, (x, 0, 5));
  </code></pre>
  
  <p>But after evaling that cell I don't get any output? There isn't an error or
  anything, it just doesn't display anything.</p>
  
  <p>Another test :</p>
  
  <pre><code>from sympy import *
  from sympy.plotting import plot, plot_parametric
  import math
  import numpy as np
  import pandas as pd
  import matplotlib.pyplot as plt
  
  
  expr = x**2 + sqrt(3)*x - Rational(1, 3)
  lf = lambdify(x, expr)
  
  fig = plt.figure()
  axes = fig.add_subplot(111)
  
  x_vals = np.linspace(-5., 5.)
  y_vals = lf(x_vals)
  
  axes.grid()
  axes.plot(x_vals, y_vals)
  
  plt.show();
  </code></pre>
  
  <p>So Im not sure what I'm doing wrong here, I'm not getting any errors though? </p>
  
  <p>If the virtual environment content is of any interest here's a tree of that :
  <a href="https://bpaste.net/show/0bcb2c219d7e" rel="noreferrer">venv</a></p>
  
  <p>I'm running this on Linux Ubuntu. The virtual environment that it's running in can be seen in the above paste link</p>