# find intersection points of a line and a curve.

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NAVNEET NAYAN on 20 Feb 2021
Edited: Adam Danz on 20 Feb 2021
I am attaching here the plot. I want to get the intersection points of the horizontal red line with the curve. Also, I want to draw the vertical lines from these intersection points. How both of these tasks can be done? In case, question is not clear feel free to comment.
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### Accepted Answer

Adam Danz on 20 Feb 2021
Edited: Adam Danz on 20 Feb 2021
There are several ways to get the x values at each intersection of the y-value. The simplest solution is to use the intersections() function from the file exchange (I show a similar demo in this answer, "method #2").
That function will return the (x,y) coordinates of the intersection points. Use the x values to plot vertical lines using xline().
% x is a vector of x-values at each intersection
arrayfun(@xline,x)
Or, if you're more comfortable with for-loops,
for i = 1:numel(x)
xline(x(i))
end
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NAVNEET NAYAN on 20 Feb 2021
Yes you are correct. I had reversed. Thank you for solving the query and explaining it too.

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