Thanks for some useful help :D
I have a problem constructing parametric equations... >< :$
and a few cartesian equations.
1. x=t2-2t, y=t2+2
2. x=t2+t, y=(t2/2) - 3t
3. x=3[t+(1/t)], y=4[t-(1/t)]
4. x=1/2 (at+a-t), y=1/2 (at-a-t)
5. x=7(sec@+tan@), y=7(sec@-tan@)
6. x=t+...