Thevenin Voltage and Resistance Calculation for Circuit with Current Sources

[Yaaaldi]

Homework Statement

Find the thevenin voltage and thevening resistance of the circuit.

[PLAIN]http://img573.imageshack.us/img573/2525/thevening.png

The Attempt at a Solution

The posted answers for the question are 5v and 1k ohm. But I can't see how the thevenin resistance is 1k ohm. Can anyone explain? I see the 5 and 1 being in parallel giving 5/6 k ohm.

edit: think I figured it out as I posted it. current sources get replaced by open circuit to calculate thevenin resistance

 

[vela]

Yes, that's correct. You set sources to 0, so a current source would be replaced by an open circuit since no current flows through it.