Phase portrait of the system in a rectangle

The two above are a system

How to display the phase portrait of the system in a rectangle Including the special point /idk if special is the correct work in english/ and how to display a tangent vector to each of the displayed not special phase curves?

[Stefani Stefanova]

function PhasePortrait
clc;
%data:
[x,y] = meshgrid(linspace(-1,2,20));
dx = 2*x-y-5;
dy = 3*x-2*y-9;
quiver(x, y, dx, dy)
axis([-1 1 -1 1])
% hold on
quiver(x, y, dx, dy);
title('Phase portrait')
axis tight
%plot(x(1), y(-3), "Marker","*", "Color", 'b');
end

this is what ive written by when i try to mark my specific point (1, -3) it doesnt work

Answer 1

[Ameer Hamza]

You can use quiver(). For example,

[x,y] = meshgrid(linspace(-1,1,20));

dx = 2*x-y-5;
dy = 3*x-2*y-9;

quiver(x, y, dx, dy)
axis([-1 1 -1 1])

Also see my answer here: https://www.mathworks.com/matlabcentral/answers/520864-how-to-plot-this-phase-portrait-correctly

[Stefani Stefanova]

Okay, thank you, but how to display the tangent vector to each of the displayed not special phase curves?

[Ameer Hamza]

It shows tangent vectors. Can you show an example?

[Stefani Stefanova]

No, i dont have an example. so my specific point ot whatever its called in english is (1, -3), but how to mark it with a star? the task says to each of the not special phase curves to draw a tangent vector

[Ameer Hamza]

This show how you can mark the specific point

[x,y] = meshgrid(linspace(-5,5,20));
dx = 2*x-y-5;
dy = 3*x-2*y-9;
quiver(x, y, dx, dy)
axis([-5 5 -5 5])
hold on
plot(1, -3, '*', 'MarkerSize', 8, 'LineWidth', 1)

[Stefani Stefanova]

Okay thank you again! so the only left thing to do is the tangent vectors to each of the displayed not special phase curves

[Ameer Hamza]

Can you manually draw on the image to show which point you want?

[Stefani Stefanova]

I think they want something like this:

i have already displayed the litlle red vectors and now i have to displya the black vectors but how?

and also my little red vectors are in one direction, the pic is just for an example

[Ameer Hamza]

Try this

[x,y] = meshgrid(linspace(-5,5,10));
dx = 2*x-y-5;
dy = 3*x-2*y-9;
quiver(x, y, dx, dy);
hold on
streamline(x, y, dx, dy, [-5:0.4:5 -5:0.4:5], [5*ones(1,26) -5*ones(1,26)])
axis([-5 5 -5 5])
plot(1, -3, '*', 'MarkerSize', 8, 'LineWidth', 1)

[Stefani Stefanova]

THANK YOU SO SO SO MUCH!!!!! That really helped me!

[Ameer Hamza]

I am glad to be of help!!!