Function + Polar Trace TI-Nspire allows for graphing of parametric, Cartesian and polar graphs on the same axes. What happens when we trace a point in both Cartesian and polar coordinate systems? In this graph/constuction, as you drag point D on the graph of y=sin(3t), the point on the polar rose, r(ø) = sin(3ø), also moves so that you can see or explain the relationship between the two coordinate systems. The coordinates of D and the converted radian-degree angle measure is on the screen, but not 'r'. The clever mathematical conversions are hidden, but easily exposed. Do you know that you can graph polar functions in parametric mode? Just define r(ø) = on a Calc page then set up these parametric functions: x(t) = r(t)*cos(t) y(t) = r(t)*sin(t) This, and the entire construction process are explained and demonstrated in this document. This file does work in all versions of TI-Nspire. If you are using version 1.3 released Jan 2008 just replace the parametric (polar) graph with a 'real' Polar graph. The point P is not really 'on' the graph anyway.