Found an error but it doesn’t solve my problem, Lambda should've been renormalized to 1/3 since the current configuration of the problem didn't have 1/N in front of it EDIT- this doesn't solve my problem! now the solutions are 1 and 1/3 (found a calculation error) - this doesn't match the derivative method OR the official possibly wrong results! The odd thing is, taking A to be a zeros matrix which is what I accidentally did after setting lambda =1/3, yielded the same results my friends got - why is that?