lab11

syms x;
syms y;
#a = [1,2,3;2,4,4;3,4,3];
#a = [1,0,0;0,4,0;0,0,-20];
a = [2,0,0;0,-6,0;0,0,-3];
f = @(x,y) a(1,1)*x^2 + 2*a(1,2)*x*y + a(2,2)*y^2 + 2*a(1,3)*x + 2*a(2,3)*y + a(3,3);
ezplot(f(x,y));

I = 3;
R = [a(1,1),a(1,2);a(1,2),a(2,2)];
disp(det(R));
D = a;
disp(det(D))
K = det(R) + det([a(1,1),a(1,3);a(1,3),a(3,3)]) + det([a(2,2),a(2,3);a(2,3),a(3,3)]);
disp(K)

if(det(R) > 0)
  #disp('Elispa');
  if(det(D) != 0)
    if(I < 0 && det(D) < 0)
      disp('Elispa');
    else
      disp('Conica vida');
    endif
  else
    disp('Punct');
  endif
elseif(det(R) < 0)
  #disp('Conica vida')
  if(det(D) != 0)
    disp('Hiperbola');
  else
    disp('Pereche de drepte concurente');
  endif
else
  #disp('Punct dublu');
  if(det(D) != 0)
    disp('Parabola');
  else
    if(K < 0)
      disp('Pereche de drepte paralele');
    elseif(K == 0)
      disp('Pereche de drepte confundate')
    else
      disp('Conica vida');
    endif
  endif
endif