pan class="o">*</span><span class="p">(</span><span class="mf">1.0_rp</span> <span class="o">-</span> <span class="nb">COS</span><span class="p">(</span><span class="n">deg2rad</span><span class="p">(</span><span class="n">eta</span><span class="p">))))</span><span class="o">/</span><span class="p">(</span><span class="mf">1.0_rp</span> <span class="o">-</span> <span class="nb">EXP</span><span class="p">(</span><span class="o">-</span><span class="mf">2.0_rp</span><span class="o">*</span><span class="n">A</