title: Plotting points on a graph?
body: <p>I have a function and I want to draw points on that function.</p>
  
  <p>For example:</p>
  
  <pre class="lang-py prettyprint-override"><code>def f(x):
      return x ** 2 + 2 * x + 4
  
  x_val= np.linspace(-6,6)
  graph = f(x_val)
  
  plt.plot(x_val, graph)
  </code></pre>
  
  <p>This will give the function evaluated at <code>x_val</code>.</p>
  
  <p>I want to plot points on the graph at <code>f(-2), f(2)</code> like this.</p>