1. The problem statement, all variables and given/known data I am trying to figure out how the formula for the force between two anti-parallel wires differs from the formula for parallel wires. 2. Relevant equations B=μ0I/2∏R Force between two parallel wires = μ0LIaIb/2∏d 3. The attempt at a solution I understand that d is the hypotenuse made by the x and y distances between the two parallel wires. I also understand that if the two currents run in parallel they will attract, but if they run anti-parallel they will repel. What I don't understand is how to manipulate the formula to calculate the anti-parallel force. At first I thought it would just be the negative value of the attractive force, but I am unsure. My other thought was that the repelling force would be based off of the net magnetic force between the two wires. I am very lost. If anyone felt like clearing this up for me I would very much appreciate it.