释义 |
real function A function from the set R of real numbers (or a subset of R) to R. Thus, if f is a real function, then, for every real number x in the domain, a corresponding real number f(x) is defined. If a function f: S → R is defined by giving a formula for f(x), without specifying the domain S, it is usual to assume that the domain is the largest meaningful subset S of R. For example, if f(x) = 1/(x − 2), the domain would be taken to be R\\ {2}; that is, the set of all real numbers not equal to 2. If , the domain would be the closed interval [−3, 3].
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