Example

T(n) = 3T(n/4) + nlgn

a=3, b=4, f(n) = nlgn

n^{log₄ 3} = O (n^0.793)

f(n) = , $\epsilon$$\approx$ 0.2, Case 3

For large n, af(n/b) = 3(n/4)lg(n/4) $\leq$ 3/4nlgn = cf(n), c=3/4

T(n) = $\Theta(nlgn)$