bx|) - x_1 \frac{x_1-|\bx|}{2|\bx|}, & \text{if }\ |\bx| \neq 0, \\   
      0, & \text{if }\ |\bx| = 0,  
      \end{cases}\\, 
      \end{align*}
      where $|\bx| = \sqrt{x_1^2+x_2^2}$. To help you with the analysis of this system, we
      set up <script>document.write(notebook_link('pend', 'attractivity_vs_stability', link_text='this python notebook'))</script>.  Take your time to understand
      the code in it, and then answer the following questions.

      <ol type="a">

        <li>Find all the e