Excess number density of fermions in the Universe

In Kolb and Turner’s book, it is given that if the chemical potential of the fermionic species if not taken to be neglible then the excess fermion number density is given as follows.

$n_+$ – $n_-$ = $frac{g}{2pi^2}$ $int_0^ infty$ $E(E^2 – m^2)^{1/2} dE$ x $Bigg[$ $frac{1}{e^{(E-mu)/T} + 1}$ – $frac{1}{e^{(E+mu)/T} + 1}$ $Bigg]$
= $frac{gT^3}{6pi^2}$ $Bigg[$ $pi^2$ $Big( frac{mu}{T} Big)$ + $Big( frac{mu}{T} Big)^3$ $Bigg]$.

I am getting the first term by doing the integration, but not the second term.

P.S. It is assumed that the chemical potential of an anti-particle is negative to that of the particle.