Data Points where I need to identify where a tangent to the graph is vertical
2 views (last 30 days)
Show older comments
Hey Experts I need help to identify where a tangent is vertical on a data set that is represented by a graph.
Data_X = [.1 .2 .45 .79 1.29 1.35 1.4 1.925 2.45 2.95 3.36 3.82 3.99 4.16 4.32 4.415 4.51 5.4 5.46 5.575 5.69 5.68 5.73 5.78 5.83 5.93 6.8 6.11 6.15 6.19 6.21 6.24 6.25 6.26 6.14 6.5 6.6 6.7 6.5 6.35 6.2 6.7 6.15 6.14 6.1 5.99 5.85 5.7 5.58 5.61 5.71 5.72 5.57 5.25 4.97 4.64 4.45 4.37 4.31 4.28 4.32 4.39 4.42 4.45];
Data_Y = 1:length(Data_X);
I need to identify the data point where the tangent to the graph is vertical. I cannot make a function for this, because its only a small part of the graph. But if I can find it here, I can find it everywhere.
It cannot be found by maximum, since this is a small piece and there is a bigger value farther down, and Im interested in all of the vertical tangents.
Is there a person that can help me?
Best Retard Mikkel
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/160757/image.jpeg)
1 Comment
Roger Stafford
on 15 Feb 2017
Your request is not clear to me. To make a graph of your data, it must be plotted against another variable. If that other variable is simply the index of the ‘data’ elements, it would be impossible to have a vertical tangent. If the other variable is not this, what is it?
Answers (1)
Star Strider
on 15 Feb 2017
I do not see that ‘Data’ has a ‘vertical’ slope anywhere. Perhaps supplying an independent data vector (since ‘Data’ is the dependent variable) and defining ‘vertical’ would help. The derivative provided by the gradient function would define the slope of ‘Data’ at any point, and nowhere is it high, much less approaching infinity (the definition I would use to define ‘vertical’).
dData = gradient(Data);
figure(1)
plot(Data)
hold on
plot(dData)
hold off
grid
See Also
Categories
Find more on Graph and Network Algorithms in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!