# Help with the following error with quiver

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Amy Topaz on 24 Mar 2022
Edited: Rik on 24 May 2022 I am getting the above error using the function quiver for vector field
x = -4e-7:0.1e-12:4e-7;
y = -4e-7:0.1e-12:4e-7;
[X,Y] = meshgrid(x,y);
HX = (atan(((g/2 + X)./Y);
HY1 = (cos((g/2 + X).^2 + (Y).^2/(g/2 - X).^2 + (Y).^2));
H = sqrt(HY1.^2 + HX.^2);
quiver(H,X,Y);
Rik on 24 May 2022
Editing away your question is very rude, please don't do it again.

Sam Chak on 24 Mar 2022
Edited: Sam Chak on 26 Mar 2022
If g is assumed as the gravity, then the "Region of Repulsion" is found here. Solving the simultaneous equations and give two saddle points somewhere around and region. Check it out.
[X, Y] = meshgrid(-7:4/14:-3, -2:4/14:2);
g = 10;
U = (1/pi)*(atan(((g/2 + X)./Y) + atan((g/2 - X)./Y)));
V = (-1/2*pi)*(log((g/2 + X).^2 + (Y).^2./(g/2 - X).^2 + (Y).^2));
quiver(X, Y, U, V, 1.5)
axis square
axis([-7.5 -2.5 -2.5 2.5]) Sam Chak on 24 Mar 2022
Are you looking for 3-D vector field like this?
[X, Y, Z] = meshgrid(-7:4/14:-3, -2:4/14:2, 0:4/14:4);
g = 10;
U = (1/pi)*(atan(((g/2 + X)./Y) + atan((g/2 - X)./Y)));
V = (-1/2*pi)*(log((g/2 + X).^2 + (Y).^2./(g/2 - X).^2 + (Y).^2));
H = sqrt(U.^2 + V.^2);
h = quiver3(X, Y, Z, U, V, H); Walter Roberson on 24 Mar 2022
quiver has a few calling sequences:
• quiver(x, y, u, v)
• quiver(u, v)
• either of those followed by a scale factor
• any of the above proceeded by an axes handle
You are using three parameters, so you are either using axes, u, v or else u, v, scale. But the first parameter is not an axes so you are using u,v, scale
Did you possibly intend to use quiver3?