I have to calculate the magnetic field at point x = R/2 (R is the separation between the two coils).
I see why, for one coil, we only take the component along x from the B field as the values along y "cancel" themselves.
But if we add another coil on the other side, the values along x should also cancel themselves (since they have the same intensity at x = R/2)!
I really don't get why it's not 0 at point x = R/2. Here's a scheme of my understanding (with in red the dB field from the other coil)
If something is unclear please let me know.