Three sliders, a, b, and α adjust the general equation of a circle. Sliders h and k transform the equation horizontally and vertically. Slider a set the radius and α allows the circle to rotate. 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? A horizontal circle? What settings changes are needed to set the rotation of the ellipse to 45°, 120°, 215°, or 330°? What settings create a circle? What settings create a point?