cy</a><span class="special">&amp;);</span>
</pre>
<p>
        Returns the incomplete elliptic integral:
      </p>
<p>
        <span class="inlinemediaobject"><img src="../../../equations/ellint_d.svg"></span>
      </p>
<p>
        Requires <span class="emphasis"><em>-1 &lt;= k &lt;= 1</em></span>, otherwise returns the result
        of <a class="link" href="../error_handling.html#math_toolkit.error_handling.domain_error">domain_error</a>
        (outside this range the result would be complex).
      </p