# How to draw a semi parabola plot for a certain range (0, 1) and (0 90)?

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Amjad Iqbal on 16 Jan 2023
Edited: Amjad Iqbal on 7 Mar 2023
Dear MATALAB community,
I need to get a plot as attached in image.
X-axis ranges (0, 1) and Y-axis ranges (0, 90)
I need to create certain zones and add scatters point in that semi-perbolic plane.
I have scattering points but I want to present and overlap results with this plane to idetify typ of data.

Amjad Iqbal on 7 Mar 2023
Edited: Amjad Iqbal on 7 Mar 2023
@Jasvin Thank you for your suggestions,
I obtained parabola plane for my task as given below.
y = linspace(0, 1, 100);
x = y - y.^2;
% Plot the data
plot(x*4, y*95, 'linewidth', 2)
% Add axis labels and title
xlabel('Entropy')
ylabel('\alpha')
hold on
title('H - \alpha plane')
xlim([0 1])
ylim([0 90])
set(gca,'FontSize',12);

Jasvin on 7 Mar 2023
Assuming that you have the code to generate the parabola (if you don't then you can refer to the below MATLAB Answer, https://www.mathworks.com/matlabcentral/answers/67272-how-do-i-plot-parabolas-and-other-functions-in-matlab) and the scattering points refer to the endpoints of each zone/region, you can first plot the parabola and then use the hold on command (https://www.mathworks.com/help/matlab/ref/hold.html) to overlay plots on top of the parabola.
You can also make use of functions like the rectangle to plot specific shapes (https://www.mathworks.com/help/matlab/ref/rectangle.html).

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