When you study the growth of a function you want to consider very large numbers. "Very large numbers" transforms mathematically in the concept of limit. If (n>10^{1000047+E}) then **nlog n** will start to be bigger than 1000047n, and thus when we check the behaviour you can exclude this linear term.

You must undestand that this is a theoretical approach, in practice for a lot of small values these constants are important in the running time.