In advanced mathematics, we often encounter the problem of calculating the limit of function. Especially when the function limit does not exist (not infinite), people always don't know how to explain it. In fact, this problem can be proved by Heine's theorem (or the principle of resolution) given by the German mathematician Heine.

Heine theorem (also known as resolution principle) is a bridge between the limit of sequence and the limit of function. With this relationship, the transformation of limit calculation can be realized in many cases.