Medea(play)

Explain and analyze why Medea(play) is a tragedy. but she also is a hero. What is you own definition of tragic hero?
Use Soren Kierkegaard, Fyodor Dostoevsky, Friedrich Nietzsche' perspectives in Existentialism (Life is suffering) to analyze a scene that Meadea use his son to kill her husband who betrayed her. and husband's new wife (queen), and Medea kill her son in the end as well.