Master theorem and extended Master theorem

Question

I have doubt regarding Master theorem.In which situation we should use Normal Master theorem/extended Master theorem?

Comments

If recurrence relation is of the form

T(n)=aT(n/b)+f(n) Then use master theorem

and use Extended Master theorem when  recurrence relation is of the form

T(n)=2T(n/2)+ nlogn

here a=2, b=2 so, n^{log₂ 2} =n and f(n)= nlogn

n^{log₂ 2} =n is smaller by logn. So we can use Extended Master theorem

T(n)= Θ(n (log n)²)