"Limit" is the concept underlying calculus, a branch of mathematics, and in a broader sense means "infinitely close and never reachable". The word "limit" in a broader sense means "infinitely close and never reachable". A "limit" in mathematics is a variable in a function which, in the course of perpetual change to a greater (or lesser) value A, gradually approaches a definite value A and "never reaches A" ("never equals A"). In the process of "never being equal to A, but being equal to A' is enough to obtain highly accurate calculation results," the change of this variable is artificially defined as "always approaching without stopping," and it has a "tendency to constantly approach the point A with extreme accuracy. It has a "constant tendency to get extremely close to point A". The limit is a description of a "state of change". The value A to which the variable is always approaching is called the "limit value" (which can of course be represented by other symbols).