Dear every body. I have one problem of my homeworks that I can solve. Please help me! Thank you. Construct in k-spaceof the first 4 Brilloun zones of a square lattice in the extended zone scheme & show that the 1st, 2nd, 3rd, 4th Brilloun zones have all the same area. Construct these pieces in the reduced zone scheme & the rough shape of the Fermi surface for the system with 4 free electrons/atom.