1. The problem statement, all variables and given/known data A few examples done in class that I didn't understand are as follows: (Find out if convergent or divergent) integral 0-->infinity ( x / (x^3 + 1) ) integral 1-->infinity ( (2+e^(-x) ) / x ) 2. Relevant equations None 3. The attempt at a solution Basically, I have NO idea where to begin. My professor seriously glossed over this concept in class; he basically just stated the theorem and then said "just compare it to another function". What functions? How? How do we know if we need a converging or diverging function? Can I get a careful walkthrough of some example problems so that this concept sinks in? Thank you.