(maxNDX);
h1 = plot(domain, f(domain), <span class="string">'-r'</span>, <span class="string">'LineWidth'</span>, 3);
h2 = plot(domain, t(domain), <span class="string">'--b'</span>, <span class="string">'LineWidth'</span>, 2.5);
legend([h1, h2], {<span class="string">'f(x)'</span>, <span class="string">'f_{quad}(x)'</span>}, <span class="string">'Location'</span>, <span class="string">'NorthWest'</span>);
plot(Xk, f(Xk), <span class="string">'.k'</span>, <span class="string">'MarkerSize'</span>, 25);
plot([