Electric potential of two point charges

The electric potential of two-point charges.

 The electric potential V around a charged particle is given by where is the permittivity constant, q is the magnitude of the charge in coulombs, and r is the distance from the particle in meters.
V=1/4pie0 (q/r)


>> eps0=8.85e-12; q1=2e-10; q2=3e-10;
k=1/(4*pi*eps0);
x=-0.2:0.01:0.2;
y=-0.2:0.01:0.2;
[X,Y]=meshgrid(x,y);
>> r1=sqrt((X+0.25).^2+Y.^2);
r2=sqrt((X-0.25).^2+Y.^2);
V=k*(q1./r1+q2./r2);
mesh(X,Y,V)
xlabel('x (m)'); ylabel('y (m)'); zlabel('V (V)')