- Open a browser at the address http://arcikam.kam.mff.cuni.cz:12080/
- Click "Browse published Sage worksheets", and then choose from the list.

- Open a browser at the address http://arcikam.kam.mff.cuni.cz:12080/
- Log in by using your own credentials or by using a public account. Id:
*Guest*, pw:*8GxPsCOs*. Id is case sensitive. Do not change pw!

You shall also register to receive an account, since the anonymous account will soon be blocked - as soon as most of you will register. - Then just click "New worksheet", give it a name and you may start experimenting.

- To define a vector or a matrix
`b=vector([1,0,5,3]);`

A=matrix(QQ,[[1,4],[3,4],[5,1]]);

or equivalently.`A=matrix(QQ,3,2,[1,4,3,4,5,1]);`The first optional parameter is the field. We will need the following ones:

`ZZ`- integers,`QQ`- rationals,`RR`- real numbers,`CC`- complex numbers,`GF(`*k*`)`- the unique finite field with*k*elements.The optional second and third parameters are the numbers of rows and columns.

- To get a reduced row echelon form
`A.rref()`or`A.echelon_form()` - To transpose, multiply or invert matrices
`transpose(A)`or

A*B

A^{-1}`A.inverse()` - To combine two matrices together
`A.augment(B)`- horizontally

`A.stack(B, subdivide=True)`- verticallyThe optional parameter

`subdivide=True`is for aestheticeal purposes only - it draws a line between the parts.