I was looking at an integral the other day:

.

And I was told that it varies as 1.5x/log x, because I was trying to show that:

, where

can be taken as 27.

I mean, I've taken BC Calc two years ago, I took Linear Algebra last year, and I will take Differential Equations in the coming fall, but I have never heard of the term "vary" when dealing with integrals, or perhaps I know of a term with a similar definition.

Would anyone mind explaining to me what it means that the integral varies as 1.5x/log x? (and/or give me a useful link talking about it).