Having troubles with some circular function and log questions :( :( :(

[hello_kitty]

Hey Guys,
I'm having some troubles with these questions. Any help would be appreciated!! thanks 

Having troubles with some circular function and log questions :( :(

[Greatness]

With the trig functions i think youre confusing yourself/you dont fully understand it. When you find an angle that you dont know, work your way aorund the unit circle to you find that angle and quadrant. Once you know the quadrant ask yourself if that function is positive or negative in that quadrant. Once you do that, think what angle is the equivalant angle in this quadrant? -> You will have to know these, what i mean by this is: 5TT/2 is the same as TT/2, likewise, -5TT/4 is the same as -TT/4 and 7TT4. When you have those bigger angles always get them back to their equivalent simple forms. The questions where you have to find the angle is just the opposite process, so you get a negative or positive value. Ask yourself where is this trig function negative or positive (cast) then you find the angles that way.
Have a go at those yourself!

[hello_kitty]

Thanks I sort of get that Im still just gettin ga bit confused

[Kiro Kompiro]

Just with the unit circle stuff:  don't forget that the sin is the y co-ordinate of the point on the unit circle's circumference that the angle intersects with, and cos is the x-coordinate of the point.  So just like like the usual x-y axes, y (=sin) is always positive on the top half of the circle and negative in the bottom half of the circle, and x(=cos) is positive to the right and negative to the left.  A negative angle just means start from 0 and go clockwise, and a positive means start from 0 and anti-clockwise.