1. Do you know how to express in terms of sin and cos? What does represent? Surely you can do this and do the algebra.
2. Pick an (x,y) coordinate such that it's situated in quadrant IV, i.e. a positive x with a negative y. A triangle can be created using the values of x and y and then it's a matter of applying the definitions of sin(t), cos(t), and tan(t).