MATLAB: Horzcat function joins 1 end of line to the other end.

Question

Hi there, if you can see from my data, there's a problem with the graph. the point on the Left joins with the point around zero on the X-axis. I know that this is because of horzcat but I need to use horzcat for a later point. Can anyone come up with a solution as I've triped swapping the range at the start and it says 'vectors must be the same length' This is my code:

[data, titles, r]=xlsread('Tidal Sites.xlsx');
A=data(:,9);
B=data(:,10);
C=data(:,11);
D=data(:,12);
E=data(:,6);
F=titles(:,2);
x1=linspace(E(1)/24., 7.3826475-(0.527331964/2)-E(1)/24, 10000);
y1=det(A(1))*((exp(1).^(det(-B(1)).*x1))).*cos((det(C(1)).*x1)+det(D(1)));
figure, plot(x1,y1), hold on
x2 = E(1)/24 - cumsum(fliplr(diff(x1)));
y2 = y1(1:end-1);
x = horzcat(x2, x1);
y = horzcat(y2, y1);
plot(x, y)

Answer 1

x = horzcat(x2, nan, x1);
y = horzcat(y2, nan, y1);