<a class="mw-redirect" href="https://en.wikipedia.org/wiki/Gottfried_Leibniz" id="mwWg" rel="mw:WikiLink" title="Gottfried Leibniz">Gottfried Leibniz</a> demonstrates <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Integral_calculus" id="mwWw" rel="mw:WikiLink" title="Integral calculus">integral calculus</a> for the first time to find the area under the graph of <i id="mwXA">y</i> = <i id="mwXQ">ƒ</i>(<i id="mwXg">x</i>).