Past exam of the mathematics course of the University of Cambridge / 2021 / ii / Paper 3 / 34B / b / Solution

TakeTheir integer span consists exactly of the cubic points together with the body-centre points, so the BCC set is a Bravais lattice. Using the inverse matrix supplied in the question, reciprocal primitive vectors areThese generate a face-centred cubic lattice; thus the reciprocal lattice of BCC is FCC, with the displayed scale.