Some materials (semi-metals) have the following dispersion relation for electrons (+ sign) and holes (- sign ): E = thurk (1) where up is the characteristic velocity. (a) Please find the density of states g( E) if this material is a 2D material (e.g. graphene). (b) Please find the density of states g(E) if this material is in 1D (e.g. metallic carbonnanotube)