Finding the position vector of uniform circular motion

[LavastormSW]

Homework Statement

Write an equation for one component of the position vector as a function of the radius of the circle and the angle the vector makes with one axis of your coordinate system. Calculate how that angle depends on time and the constant angular speed of the object moving in a circle.

Homework Equations

a = v² / r
D = 2∏r
v = D / t

The Attempt at a Solution

I really don't know where to begin. The lab book says to look at an equation in the textbook that doesn't exist, or, if it does, that I can't find.

 

[Liquidxlax]

x = rcos(wt)
y = rsin(wt)

for position where w is the angular velocity

if r is constant

dx/dt = -rwsin(wt)
dy/dt = rwcos(wt)