Help us caption and translate this video on Amara.org: http://www.amara.org/en/v/B2v0/ Esercizi: http://www.khanacademy.org/exercise/unit_circle Traduzione in Italiano del video The unit circle definition of trigonometric function http://www.youtube.com/watch?feature=player_embedded&v=6Qv_bPlQS8E http://www.khanacademy.org/video/the-unit-circle-definition-of-trigonometric-function?playlist=Trigonometry