[texhax] how to typeset a matrix

[kyanh]

Hello,

I have searched through google but I could typeset the following matrix:
   http://img401.imageshack.us/img401/437/matrixxbr6.jpg
   ( or: http://files.myopera.com/nducphuong/files/ma_tran_cheo.bmp )

A member of VietTUG asked me at
http://viettug.org/ao/component/option,com_simpleboard/func,view/catid,5/id,3313/#3313
but I failed to help him!

How can we typeset that matrix ?

Thank you for helps.

Regards,

kyanh