e^x- 1~x(x→0)、e^(x^2)- 1~x^2(x→0)。 Limit is one of the most basic concepts in other branches of calculus and mathematical analysis, and the concepts of continuity and derivative are defined by it.

Limit can be used to describe the changing trend of element properties in a sequence when the exponent of a sequence is getting bigger and bigger, and it can also be used to describe the changing trend of the corresponding function value when the independent variable of a function approaches a certain value.