Extracting Multiple X values for a certain Y value from a plot?
1 view (last 30 days)
Show older comments
I need to find the value of time at all the crests and troughs of the displacement (at displacement =pi/4=0.7854), i.e, Y value is constant
for the following plot (which consists of two curves)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/426218/image.png)
the code i used is:
tspan = 0:0.01:20;
a=pi/4;
b=0;
x0 = [a; b];
[t1,x] = ode45(@pend_l,tspan,x0);
X1 = x(:,1);
X2 = x(:,2);
y0 = [a ; b];
[t2,y] = ode45(@pend_n,tspan,y0);
Y1 = y(:,1);
Y2 = y(:,2);
plot(t1,X1); %linear disp vs time, i.e, red plot
xlabel('Time (s)');
ylabel('Displacement (rad)');
hold on;
grid on;
plot(t2,Y1); %nonlinear disp vs time, i.e, blue plot
0 Comments
Answers (1)
Ameer Hamza
on 24 Nov 2020
See this FEX package: https://www.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections. You can define a straight line at y = constant and find the intersection between the line and your curves.
0 Comments
See Also
Categories
Find more on Ordinary Differential Equations in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!