title: Wrong dividing in python
body: <p>As you can see from watch, <code>l[u][0]</code> must be <code>0.5</code>, but it returns <code>0</code></p>
  
  <pre><code>u = 0
  for j in range(n):
      if k == j:
          continue
      l[u][0] = -x[j] / (x[k] - x[j])
      l[u][1] = 1 / (x[k] - x[j])
      u = u + 1
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/i0T1A.png" alt="screenshot"></p>
  
  <p>What's wrong with it?</p>