Does anybody here know where i could find some good helpful videos i can watch for trigonometry?
My next test is monday and i REALLY need a good grade, Its over Mostly proving identities and Stuff like that. Or doing like tan(arctan6)

On the subject of the tan(arctan6) style stuff i know some just arent in the domain or range, but my thing is how am i supposed to figure out stuff like
sin-1(cos(Pi/2)) And stuff like that? Any help would be loved.