So I'm working through my homework, and applying the Master Theorem pretty easily, then my prof throws me a curve ball
$T(n) = 4T(3n/4) + n^4$
Now I used my usual steps of listing out what A, B, and f(n) is:
a = 4
b = 3/4
$f(n) = n^4$
but $\log_{3/4} 4$ does not work out to be a nice a number to fiddle around with in the masters theorem. So is this the right path? Or is there some special rule that applies when b = 3/4?