I'm studying Solid State Physics and I have some problems with a problem. It is stated like this: Consider a system of two charge carriers in the Drude model. The two carriers have the same density n and opposite charge (e and-e), and their masses and relaxation times are m1,m2 and r1,r2 respectively. (a) Calculate the magnetoresistance ∆ρ=ρ(B)-ρ(0), B is the magnetic induction. (b) Calculate the Hall coefficient. Hint: Consider the conductivity tensor of the combined system of the carriers I don't know how to begin with this problem, wonder if someone please can help me? // Mythbusters - "Well, here's your problem"