How to plot the region corresponding to an inequality?
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I want to plot create the region plot for the inequality
for
. In Mathematica this can be done by
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/890035/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/890070/image.png)
RegionPlot[y - x^2 >= 0, {x, -Sqrt[3], Sqrt[3]}, {y, 0, 3}, FrameLabel -> {"x", "y"}]
producing the following plot
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/890045/image.png)
How can one produce a similar plot in Matlab? The best I could do was using the spy function as follows
h = 0.01;
[x,y] = meshgrid(-sqrt(3):h:sqrt(3),0:h:3);
e = zeros(size(x));
Z = y-x.^2;
figure(1)
spy(Z >= e);
xlabel('x'), ylabel('y')
Here is another try
clear
h = 0.05;
[x,y] = meshgrid(-sqrt(3):h:sqrt(3),0:h:3);
ineq = y-x.^2 >= 0;
f = double(ineq);
figure(2)
surf(x,y,f);
xlabel('x'), ylabel('y')
view(0,90)
Any ideas? Thank you very much in advance.
0 Comments
Accepted Answer
KSSV
on 10 Feb 2022
You are good to go with second method:
h = 0.01;
[x,y] = meshgrid(-sqrt(3):h:sqrt(3),0:h:3);
% e = zeros(size(x));
Z = y-x.^2;
idx = double(Z>=0) ;
figure(1)
pcolor(x,y,idx)
shading interp
xlabel('x'), ylabel('y')
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