First find the reactions at A and F
Two reactions are at A: Ax and Ay
One reaction at F because its a roller..: Fy
Take moment about A
Use the equilibrium equations...
Now cut the truss from the middle and take the right section of the trusss
Take the moment about D, so you all have one force left to find which is F
CE
To find the force in member F
BD, you need to find the force in member F
CD
So use the Equilibrium equations.
Now use the ΣFx equilibrium equation, but use the x component of F
CD
Hope that helps ...Pleaes rate that.. thanks