Finding poinnt of interception between two lines on graph

I have the graph shown below, i want to find the point on the y axis where the red line (at a known value of x 'N(1)') intercepts the blue curve, but I keep getting an error that says "Error using matlab.internal.math.interp1, Sample points must be unique."

N= length(Kr);
Nn= zeros(N,1)+sr;
hold on
plot(Nn,Kr,"--","linewidth",2)
xlabel("Sr")
ylabel("Kr")
title("R6 Envelope")


X= interp1(s, K, Nn(1))

How can I fix this? Thanks

[Torsten]

Remove the data points (Sr,Kr) where the envelope is not a function (i.e. the points with Sr = 1).

[Joe Bennet]

Thanks man! :)

Answer 1

[KSSV]

You can use this:

https://in.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections