  We discuss the Taylor expansion approach to non-zero baryon chemical
potential ($\mu_B$) and present results on expanion coefficients of the
pressure and energy density up to the 6-th order in $\mu_B$. Calculations have
been performed with (2+1)-flavor of improved staggerd fermions (p4fat3) and
almost physical masses on lattices with temporal extent of four and six time
slices. We use the expansion coefficients to construct the isentropic equation
of state on lines of constant entropy per baryon number and various different
hadronic fluctuations. Furthermore, we estimate the radius of convegence of our
expansion, which can be seen as a method to analyze the structure of the QCD
phase diagram.
