# Circle Problem

• November 8th 2010, 04:20 PM
heatly
Circle Problem
A circle of radius 1m .
Ctr is located at x=0,y=0.
a point on circle at y=-1 .
the circle rotates thru an angle of 50 deg.
what is the x,y coordinate of the point?
How would you go about solving this?
• November 8th 2010, 04:32 PM
Prove It
$\displaystyle x = r\cos{\theta}$ and $\displaystyle y = r\sin{\theta}$.
• November 8th 2010, 04:40 PM
Plato
Quote:

Originally Posted by heatly
A circle of radius 1m .
Ctr is located at x=0,y=0.
a point on circle at y=-1 .
the circle rotates thru an angle of 50 deg.
what is the x,y coordinate of the point?
How would you go about solving this?

Every point on the unit circle looks like $\left( {\cos (t),\sin (t)} \right)$.

The point $(0,-1)$ happens it $t=-90^o$.

So rotate it $50^o$ counter-clockwise.