Drag N and observe the location of P, the intersection of the perpendicular bisector of FN and the line through N perpendicular to AB. Turn the Trace of P on to keep track of P's location, or look at the locus of P to see its complete path. What happens to your graph if you move F or the line AB? Note: when you turn off Trace, click and drag a point in the background to erase your old trace.
Emma Phillips March 2016 Phillips Exeter Academy