# Parametric equation

1. Jun 10, 2008

### evilpostingmong

1. The problem statement, all variables and given/known data
Describe motion of a particle w/ position xy

2. Relevant equations

x=cospi(t) y=sinpi(t)

3. The attempt at a solution
solving for t
t=x/cospi
so y=sinpi(x)/cospi
y=tanpi(x)

interval=at least one at most 2
since tan(x)=0 at pi and 2pi
and this is where the boundaries are so the particle travels from pi and 2pi counterclockwise
but the textbook has a different (but reasonable) answer in that it squares cos pi and
sin pi to equal 1 and uses the circle equation but ends up with the same diagram and
direction. If I went wrong, can you please tell me where I went wrong since my answer
seems legit to me.

2. Jun 10, 2008

### Vagrant

x= cos$$\pi$$t
should become
t=$$cos^{-1}x$$/$$\pi$$

3. Jun 10, 2008

### tiny-tim

have some π …

Hi evilpostingmong!