# Finding an error in a partial integration [closed]

There must be an error in this partial integration but I do not see it. Do you see it?

• This is not a question about math education. It is a question about mathematics. Nov 29 '20 at 19:09

The term in parentheses in the middle expression should be the change in $$x\frac{1}{x}$$ from $$x = 1$$ to $$x = 2$$ (which evaluates to zero), not just $$x\frac{1}{x}$$ (which evaluates to $$1$$).
• @SueVanHattum Why not? That particular integration-by-parts trick would work a treat if the integrand were $1/x^n$ with $n > 1$, so it's fairly natural to give it a try when the integrand is $1/x$. Dec 1 '20 at 22:56