           </p>
            </td>
<td>
              <p>
                Widely used
              </p>
            </td>
</tr>
<tr>
<td>
              <p>
                root_half_pi
              </p>
            </td>
<td>
              <p>
                √ π/2
              </p>
            </td>
<td>
              <p>
                1.25331
              </p>
            </td>
<td>
              <p>
                Widely used
              </p>
            </td>
</tr>
<tr>
<td>
              <p>