Xk, Xk], [ymin, f(Xk)], <span class="string">':k'</span>);
plot(maximum, t(maximum),<span class="string">'.k'</span>, <span class="string">'MarkerSize'</span>, 25);
plot([maximum,  maximum], [ymin, t(maximum)], <span class="string">':k'</span>);
<span class="comment">% x^(k)</span>
annotation(gcf,<span class="string">'textbox'</span>        , [0.65 0 0.09946 0.11] , <span class="keyword">...</span>
               <span class="string">'String'</span>         , {<span class="string">'x_{k}'</span>}           