DrawingAPI an ellipse

programming flash
1

[color=black]**I want to draw a ellipse using a function that looks like this :

function crearecerc(mcClip:MovieClip)
{
     nRadius=parseInt(raza.text);
     nX=parseInt(corx.text)+X;
     nY=parseInt(cory.text)+Y;
     mcClip.beginFill(parseInt(culoare_t.text, 16),100);
     mcClip.lineStyle(1,parseInt(culoare_t.text, 16), 100);
    var nAngleDelta:Number = Math.PI / 4;
    var nCtrlPoint:Number = nRadius/Math.cos(nAngleDelta/2);
    var nAngle:Number = 0;
    var nRx:Number = 0;
    var nRy:Number = 0;
    var nAx:Number = 0;
    var nAy:Number = 0;
    mcClip.moveTo(nX + nRadius, nY);
    for (var i:Number = 0; i < 8; i++) {
      nAngle += nAngleDelta;
      nRx = nX + Math.cos(nAngle-(nAngleDelta/2))*(nCtrlPoint);
      nRy = nY + Math.sin(nAngle-(nAngleDelta/2))*(nCtrlPoint);
      nAx = nX + Math.cos(nAngle)*nRadius;
      nAy = nY + Math.sin(nAngle)*nRadius;
      mcClip.curveTo(nRx, nRy, nAx, nAy);
    }
     mcClip.endFill();
}

This function creates a circle but I want to create an ellipse knowing just the center , right distance and down distance like in this figure :
figure
mcClip is the movie clip .
the center and the distances I take from a input text.**[/color]