Master Method: $T(n) = 10T\Big(\frac{n}{2}\Big) + \frac{n^4}{\log(n)}$
In order to apply Case 3, you have to show that $\frac{n^4}{\log n} = \Omega(n^c)$ for some $c &gt; \log_2 10$, as well as the regularity condition (which holds for functions of the form $n^\alpha \log^\beta n$).

You take it from here. Hint: $4 &gt; \log_2 10$.