how does the direction ( clockwise or counterclockwise effect the values of the unit circle? what does it mean?
I am not sure if this link will work but the idea is that if you went around clockwise from the +x axis you would start from the bottom of the table. In your new first quadrant, the old third quadrant, sin would be negative but cos would still be plus etc.
http://www.google.com/imgres?imgurl=http://img.asiantown.net/members/24209/cfunctions.jpg&imgrefurl=http://pc40sw07.blogspot.com/2007/02/hey-guys-sorry-for-late-post.html&h=870&w=419&sz=82&tbnid=xKHugv_Bx4MTYM:&tbnh=324&tbnw=156&prev=/images%3Fq%3Dunit%2Bcircle%2Bchart&zoom=1&q=unit+circle+chart&usg=__ITpEBSs9gLS9ZmZFk-z6nIRyl0g=&sa=X&ei=Bud7TdSAAsqBtgeKwKm6BQ&ved=0CBkQ9QEwAg