$T(n)=2T(n/2)+n\log n$ and the Master theorem
$\log n$ grows slower than $n^\epsilon$ for any $\epsilon&gt;0$. Thus $n\log n$ grows slower than $n^c$ for any $c&gt;1$. However, the third case of the Master theorem requires the existance of a $c&gt;1$ so that $n\log n$ grows at least as fast as $n^c$ (up to a constant factor).

The function is covered by the second case of the Master theorem as given in Wikipedia.