Cartesian Coordinates

Move A! Use the input bar to make points B-F that have the same positions as the blue points.
Make vectors b-f pointing at the blue points.

You can enter an object into the worksheet either by using a tool or by entering a command in the input bar. Right of the input bar, there is a menu of all commands. When it comes to points, you don't need a command. Try entering following in the input bar:

B=(3,-2) 
MyPoint=(-1,2)
v=(2,2)

GeoGebra differentiates between capital and lower case letters; it uses the naming convention that:

if the first letter is capital, a point is created

if the first letter is lower case, a vector is created

A vector has a length and a direction but it has no position. Note that you can move a vector in a work sheet without changing its coordinates.

Sometimes you want to use the x- or the y-coordinate of a point. If you have a point called A, you can find the x-coordinate and the y-coordinate respectively by writing

x(A) and y(A)

These coordinates can be used when making new points. As an example you can enter B=(x(A),y(A)+1) in the input bar

There are several variants of the commands Point and Vector. These commands can be used to make conversions between points and vectors.

For more information about vectors, see Linear Algebra - Vectors.

Instead of using Cartesian coordinates, it is possible to use polar coordinates. This is what the next page is about.

by Malin Christersson under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Sweden License

www.malinc.se