an> <span class="special">=</span> <span class="identifier">dis</span><span class="special">(</span><span class="identifier">gen</span><span class="special">);</span>
  <span class="keyword">double</span> <span class="identifier">fx1</span> <span class="special">=</span> <span class="identifier">polynomial</span><span class="special">(</span><span class="identifier">x1</span><span class="special">);</span>
  <span class="keyword">double</span> <span class="identifier">fx2</span> <span class="special">=</spa