Hello. Are the following integrals equivalent: Integral from 0 to 5 of dx / x and Integral from 0 to 5 of dx / (x + dx) What about Integral from 0 to 5 of dx / (x + 2dx + dx^2) ??? If they are all equivalent, why? (I have an intuitive answer, but it has 0 mathematical foundation). Or are they not all the same? Can someone explain this strongly? Thank you!