Please help with parametric equations

Can somebody help me with the following problems? For each of the following parametric curves, describe the motion of the particle. That is, tell the type of curve, the starting point of the particle, the direction of motion, and the behavior of the particle.

1. x=sect

y=tant

t= [0, pi/2)U(pi/2, 3*pi/2)

2. x^2=(sint)^2

y^2=(cost)^2

0 less than or equal to t less than or equal to 2pi

3. x=sint

y=(sint)^2

0 less than or equal to t less than or equal to 2pi

4. x=(1-t^2)/(1+t^2)

y=(2t)/(1+t^2)

t is greater than or equal to zero