# Cartesian Coordinates

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