1. The problem statement, all variables and given/known data I want to find the force in the vertical purple member. Assuming I know the forces in all the other members, theres a problem with working out the force in the purple member. (Bear in mind, I'm using the method where I assume equilibrium at each joint in the structure, and then resolve the forces vertically and horizontally) If I look at joint A and resolve all the forces horizontally and vertically, then I would find that the vertical purple member must have a force in reaction to the vertical component of the force carried by the diagonal member. But if I look at joint B, it would be found that the vertical purple member has zero force, which contradicts what was found in joint A. I'm stuck on this.