Drawing plane and coordinate system

The applets are started by clicking the red buttons.

 Cartesian coordinates is a simple dynamical diagram illustrating the relation between the position of a point in the drwaing plane and its (cartesian) coordinates. Particular attention is paid to the coordinates' possible signs.

 Coordinate system illustrates the connection between the position of a point and its coordinates in slightly more complex situations than the previous applet. The user can mark points, draw straight lines and read off the coordinates of the cursor position. Thus the geometric aspects of certain problems (finding the intersection point of two straight lines) become linked with algebraic structures (the solution being a pair of numbers). The applet is started from the red button in its own window.

 The applet Polar coordinates illustrates the definition of the simplest curvilinear coordinate system. A sample of coordinate lines may be switched on and off. This shall give the user some feeling for the "flair" connected with these coordinates without the need of using formulae. Furthermore it offers an approach to the coordinates' behaviour at the origin, and clarifies why the angular coordinate f undergoes a jump when crossing the positive x-axis.

 The applet Oblique coordinates shows an example of such a coordinate system. A sample of coordinate lines may be switched on and off, thus illustrating the fact that oblique coordinates give rise to a "grid" on the drawing plane different from that related to cartesian (rectangular) coordinates.