Three sliders, a, b, and α adjust the general equation of a circle.[br]a set the radius and α allows the circle to rotate.[br][br]Display of [math]\frac {(x-h)²}{a²} + \frac{(y-k)²}{a²} = 1[/math]

What are the setting ranges for a, b, and α to show a vertical circle?[br]A horizontal circle? [br]What settings changes are needed to set the rotation of the circle to 45°, 120°, 215°, or 330°?[br]What settings create a circle?[br]What settings create a point?