Phase Portraits of Planar Quadratic Systems

 1. Introduction.- 2. Critical Points in Quadratic Systems.- 3. Isoclines, Critical Points and Classes of Quadratic Systems.- 4. Analyzing Phase Portraits of Quadratic Systems.- 5. Phase Portraits of Quadratic Systems in the Class mf = 0.- 6. Quadratic Systems with a Center Point.- 7. Limit Cycles in Quadratic Systems.- 8. Phase Portraits of Quadratic Systems in the Class mf = 1.- 9. Phase Portraits of Quadratic Systems in the Class mf = 2.- 10. Phase Portraits of Quadratic Systems in the Class mf = 3.- 11. Phase Portraits of Quadratic Systems in the Class mf = 4.- References.