On tryndamere it is important to build attack speed and critical strike. You don't need defense on tryndamere because your dps is of 1200. If you want you can build last item a guardian angel.
Your first item has to be phantom dancer or berserker's greaves so that you have a lot of attack speed. After that you have your phantom dancer and berserker's greaves you have to buy an infinity edge, for more damage. Now you need life steal so farm and kill and get a bloodthirster. Now you are owning people. To get them madder buy another bloodthirster and to put the cheery on the sundee, buy an infinity edge. Now you are the complete killing machine.

Hope you have fun
:)