The figure shows two planets of mass m orbiting a star of mass M. The planets are in the same orbit, with radius r, but are always at opposite ends of a diameter. This is the equation eq. I used: mv^2/r=GMm/r^2+Gmm/(2r)^2 This is what I came up with but it is not the right answer. Where did I go wrong? sqrt4pi^2/G(M+m)*r3/2 Any help would be great!