Drawing perfect circle using curveTo

programming flash
1

I have tried to draw a circle using drawing API curveTo function. But the result is not a perfect circle.
Flash documents also suggest this method.
Check this link >>
This is the code I have used to make a circle of radius R and the registration point of circle movie clip is at the center.


this.createEmptyMovieClip("circle",this.getNextHighestDepth());
circle.lineStyle(1,0x0,100);
circle.moveTo(-R/2,0);
circle.curveTo(-R/2,-R/2,0,-R/2);
circle.curveTo(R/2,-R/2,R/2,0);
circle.curveTo(R/2,R/2,0,R/2);
cirvle.curveTo(-R/2,R/2,-R/2,0);

Let me know if there is any way of achieving a perfect circle using drawingAPI.