   <span class="n">DEi</span> <span class="o">=</span> <span class="p">((</span><span class="n">dL</span><span class="o">/</span><span class="p">(</span><span class="n">kL</span><span class="o">*</span><span class="n">SL</span><span class="p">))</span><span class="o">**</span><span class="mi">2</span> <span class="p">,</span> <span class="p">(</span><span class="n">dCp</span><span class="o">/</span><span class="p">(</span><span class="n">kC</span><span class="o">*</span><span class="n">SC</span><span class=