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Example 2: a function f is uniformly continuous on the semi-open interval [0,∞) if and only if it is continuous at the standard points of the interval, and in addition, the natural extension f* is microcontinuous at every positive infinite hyperreal point. Example 3: similarly, the failure of uniform continuity for the squaring function
respectively. If these limits exist at p and are equal there, then this can be referred to as the limit of f(x) at p. [7] If the one-sided limits exist at p, but are unequal, then there is no limit at p (i.e., the limit at p does not exist). If either one-sided limit does not exist at p, then the limit at p also does not exist.
In multivariable calculus, an iterated limit is a limit of a sequence or a limit of a function in the form , = (,), (,) = ((,)),or other similar forms. An iterated limit is only defined for an expression whose value depends on at least two variables. To evaluate such a limit, one takes the limiting process as one of the two variables approaches some number, getting an expression whose value ...
The function in example 2, a jump discontinuity. Consider the function = {< = > Then, the point = is a jump discontinuity.. In this case, a single limit does not exist because the one-sided limits, and + exist and are finite, but are not equal: since, +, the limit does not exist.
Limits can be difficult to compute. There exist limit expressions whose modulus of convergence is undecidable. In recursion theory, the limit lemma proves that it is possible to encode undecidable problems using limits. [14] There are several theorems or tests that indicate whether the limit exists. These are known as convergence tests.
If is expressed in radians: = = These limits both follow from the continuity of sin and cos. =. [7] [8] Or, in general, =, for a not equal to 0. = =, for b not equal to 0.
For any continuous function, if exists, then () exists too. In fact, any real-valued function f {\textstyle f} is continuous if and only if it preserves the limits of sequences (though this is not necessarily true when using more general notions of continuity).
The inferior and superior limits at x=2 both exists and both have value 2 while the limit of the function at x=2 is not defined. Surely the example you give does have limit 2 at x=2, since in any sufficiently small neighbourhod of x=2, the function has value 2? Note that it is important that the definition of a limit omit the point f(2) when ...