Try this —
x = linspace(4, 7, 250)*1E4;
y = @(x) normpdf(x,57565.67,1743.56);
y1 = @(x) normpdf(x,54908.02,1663.82);
xp = 54698;
xlx = x<=xp;
xhx = ~xlx;
figure
plot(x, y(x))
hold on
plot(x, y1(x))
patch([x(xlx) flip(x(xlx))], [y(x(xlx)) zeros(size(x(xlx)))], 'b', 'EdgeColor','none', 'FaceAlpha',0.75)
patch([x(xhx) flip(x(xhx))], [y1(x(xhx)) zeros(size(x(xhx)))], 'r', 'EdgeColor','none', 'FaceAlpha',0.95)
plot([1 1]*xp, y1([0 1]*xp), '-k', 'LineWidth',2.5)
hold off
text([5.4 5.6]*1E+4, [1 1]*1E-5, {'\alpha','\beta'}, 'Horiz','center', 'Vert','middle', 'FontWeight','bold', 'Color','g')
Experiment to get different results.
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