Macbeth: To what extent can Macbeth be considered a tragic hero

Key quotes:

Act 1:

"Whose horrid image doth unfix my hair" - Macbeth thinks that him being king (by killing the current king) is a horrible thought and just the image of it makes his hair stand on end. Although this slowly changes.

Act 2:

"Is this a dagger I see before me, the handle toward my hand? Come let me clutch thee." - Macbeth is having a vision (suffering inwardly). This is the vision that leads him to kill Duncan and begin his downfall from hero to villain.

Act3:

"Fleance his son, that keeps him company, Whose absence is no less material to me than his Fathers" Macbeth is requesting that Fleance is killed as well. This really…