  We present results for the QCD equation of state, quark densities and
susceptibilities at nonzero chemical potential, using 2+1 flavor asqtad
ensembles with $N_t=4$. The ensembles lie on a trajectory of constant physics
for which $m_{ud}\approx0.1m_s$. The calculation is performed using the Taylor
expansion method with terms up to sixth order in $\mu/T$.
