How do I find roots of trig functions numeric values over range

This is similar to the roots of trig function thread that was just posted.  

When I Set_EnvAllSolutions:=true; and then use cos(x)=0 for example are the _B3~ and _Z3~ just place holders?  

If I want the actual numeric values over a range and I'm trying to use fsolve, I can't seem to get it to work. 

SetEnvAllSolutions:=true; fsolve(cos(x)=0, x=0..3*Pi);

I get 4.712388980 as the only answer.  I should have 3 values shouldn't I?