title: Plotting system of differential equations in Python
body: <p>I've just started to use Python to plot numerical solutions of differential equations. I know how to use <code>scipy.odeint</code> to solve and to plot single differential equations, but I have no idea about systems of differential equations. How can I plot the following coupled system?</p>
  
  <pre><code>N' = a * N - (C/(1+C)) * b * N
  C' = (C/(1+C)) * N - C + 1
  
  a = 4
  b = 7
  N(0) = 100
  C(0) = 5
  </code></pre>