clc;

U=100;
L=100*0.001;
C=50*0.000001;
R=20000;
beta=R/(2*L);
teta=0.000001;


omegan=1/(sqrt(L*C));
omegao=sqrt(omegan*omegan-beta*beta);
delta=sqrt(beta*beta-omegan*omegan);
gama= atan(omegao/beta);

a=2*sqrt(L/C);
%delta > 0
if (R > a)   
     t=[0:teta:100*teta];
     Uct=U*(1-(exp(-beta*t)/delta).*(beta.*sinh(delta*t)+delta.*cosh(delta*t)));
     it=(U/(L.*delta)).*exp(-beta*t).*sinh(delta*t);
     Urt=((2.*beta)/(delta)).*U.*exp(-beta*t).*sinh(delta*t);
     Ult=(U/delta).*exp(-beta*t).*(delta.*cosh(delta*t)-beta.*sinh(delta*t));   
elseif (R == a)   
    %delta = 0
    t=[0:teta:100*teta];
    Uct=U*(1-(1+beta*t)*exp(-beta*t));
    it=(U/L)*t*exp(-beta*t);
    Urt=2*beta*U*t*exp(-beta*t);
    Ult=U*(1-beta*t)*exp(-beta*t);
elseif (R < a)
    %delta < 0
    t=[0:0.05*teta:5*teta];
    Uct=U.*(1-(omegan/omegao).*exp(-beta*t).*sin(omegao*t+gama));
    it=(U/(omegao.*L)).*exp(-beta*t).*sin(omegao*t);
    Urt=(((2*beta)/omegao).*U.*exp(-beta*t).*sin(omegao*t));
    Ult=-U.*(omegan/omegao).*exp(-beta*t).*sin(omegao*t)-gama;

end


subplot(4,1,1);
plot(t,Uct,'red');
xlabel('t');
ylabel('Uc(t)');
hold on;
subplot(4,1,2);
plot(t,it,'black');
xlabel('t');
ylabel('i(t)');
subplot(4,1,3);
plot(t,Urt,'green');
xlabel('t');
ylabel('Ur(t)');
subplot(4,1,4);
plot(t,Ult,'blue');
xlabel('t');
ylabel('Ul(t)');