clear all
Q1=4e-12; 
Q2=-2e-12;	
e0=8.854e-12;
k=1/(4*pi*e0);  
r1=[1, 0, 1]*1e-2;
r2=[-1,0,-1]*1e-2;

X=[-3:0.1:3]*1e-2; 
len=length(X);
Y=zeros(1,len);  
Z=Y;  
P=[X' Y' Z'];   %tvorimo matriko s koordinatami tock P(x,y,z)
P(1,:)  		% tako zapišemo prvi vektor

for i=1:len
	RP1(i,:)=(P(i,:)-r1);  
	ERP1(i,:)=k*Q1*RP1(i,:)/(RP1(i,:)*RP1(i,:)')^3;
	RP2(i,:)=(P(i,:)-r2);  
	ERP2(i,:)=k*Q2*RP2(i,:)/(RP2(i,:)*RP2(i,:)')^3;
end  

ERP1(:,1); % x komponenta polja, ki ga povzroca elektrina Q2
ERP2(:,1); % x komponenta polja, ki ga povzroca elektrina Q2

E=ERP1 + ERP2;

for i=1:len
   Eabs(i)=sqrt(E(i,1)^2+E(i,2)^2+E(i,3)^2);
end
Eabs;

figure
subplot(2,1,1),plot(X,E(:,3))
grid on;
xlabel(' x     [m]');
ylabel('Ex     [V/m]');

subplot(2,1,2),plot(X,Eabs)
grid on;
xlabel(' x     [m]');
ylabel('AbsE     [V/m]');