urns the cotangent of an angle.
        </li>
        <li>
          <b>COT_DEG</b> returns the cotangent of an angle given in degrees.
        </li>
        <li>
          <b>CSC</b> returns the cosecant of X.
        </li>
        <li>
          <b>CSC_DEG</b> returns the cosecant of an angle given in degrees.
        </li>
        <li>
          <b>DELANNOY</b> returns the Delannoy numbers up to orders (M,N).
        </li>
        <li>
          <b>E_CONSTANT</b> returns the value of the base of the natu