Explore this applet to draw a circle. Follow these directions: [list][*]Click on the pencil point and move it around until you draw a full circle.[/*][*]Now change the slider to a bigger number and move the pencil point around. [br][/*][*]Now change the slider to a smaller number and move the pencil point around. [br][/*][*]Now move the red pin and make a circle again. [br][/*][*](Hit the clear trace to clear screen.)[br][/*][/list]

What equation would give you a circle?