First, there is not some "formula" which defines the classical tragedy. Instead, the philosopher Aristotle, in his Poetics, recounts his observations of thing that the best Greek tragedies had in common. Some elements of this description lie in the nature of the drama and its ritual origins, while others are simply Aristotle's opinions about the common features of the best Greek tragedies.
Andromache was a play by Euripides first performed approximately between 425 and 428 BC. The play and its performance followed the conventions of Greek tragedy in consisting of "episodes" performed by three actors and choral odes performed by a chorus that remains onstage throughout the play. As with all Greek tragedies, it was written in verse and the chorus would have sung and danced. All roles in the drama were performed by three male actors who would change costumes and masks to assume multiple roles.
As is also typical of the genre, the protagonists are of noble descent and related to the gods. A goddess, Thetis, directly intervenes in the play to bring about a happy resolution. The plights of Andromache and Peleus can invoke fear and pity. Euripides was criticized in his period at times for making his characters more petty and less noble than those found in the works of Aeschylus and Sophocles. Although other works by Euripides seem to foreshadow New Comedy, Andromache involves a typical tragic plot based on the aftermath of the Trojan War, and even the plot elements concerning marriage and children have strong dynastic implications rather than being purely personal as they are in New Comedy.