![]() ![]() For all values to the left of 2 (or the negative side of 2), g ( x ) = −1. To provide a more accurate description, we introduce the idea of a one-sided limit. However, this statement alone does not give us a complete picture of the behavior of the function around the x-value 2. As we pick values of x close to 2, g ( x ) g ( x ) does not approach a single value, so the limit as x approaches 2 does not exist-that is, lim x → 2 g ( x ) lim x → 2 g ( x ) DNE. To see this, we now revisit the function g ( x ) = | x − 2 | / ( x − 2 ) g ( x ) = | x − 2 | / ( x − 2 ) introduced at the beginning of the section (see Figure 2.12(b)). ![]() Sometimes indicating that the limit of a function fails to exist at a point does not provide us with enough information about the behavior of the function at that particular point. Use a table of functional values to evaluate lim x → 2 | x 2 − 4 | x − 2, lim x → 2 | x 2 − 4 | x − 2, if possible. We apply this Problem-Solving Strategy to compute a limit in Example 2.4. ![]() We may need to zoom in on our graph and repeat this process several times. If the y-values approach L as our x-values approach a from both directions, then lim x → a f ( x ) = L. We can use the trace feature to move along the graph of the function and watch the y-value readout as the x-values approach a. Using a graphing calculator or computer software that allows us to graph functions, we can plot the function f ( x ), f ( x ), making sure the functional values of f ( x ) f ( x ) for x-values near a are in our window.We can use the following strategy to confirm the result obtained from the table or as an alternative method for estimating a limit. If both columns approach a common y-value L, we state lim x → a f ( x ) = L.( Note: Although we have chosen the x-values a ± 0.1, a ± 0.01, a ± 0.001, a ± 0.0001, a ± 0.1, a ± 0.01, a ± 0.001, a ± 0.0001, and so forth, and these values will probably work nearly every time, on very rare occasions we may need to modify our choices.) ![]() In our columns, we look at the sequence f ( a − 0.1 ), f ( a − 0.01 ), f ( a − 0.001 ). Next, let’s look at the values in each of the f ( x ) f ( x ) columns and determine whether the values seem to be approaching a single value as we move down each column.Table 2.1 Table of Functional Values for lim x → a f ( x ) lim x → a f ( x ) We begin our exploration of limits by taking a look at the graphs of the functions At the end of this chapter, armed with a conceptual understanding of limits, we examine the formal definition of a limit. We therefore begin our quest to understand limits, as our mathematical ancestors did, by using an intuitive approach. Yet, the formal definition of a limit-as we know and understand it today-did not appear until the late 19th century. In fact, early mathematicians used a limiting process to obtain better and better approximations of areas of circles. The concept of a limit or limiting process, essential to the understanding of calculus, has been around for thousands of years. 2.2.6 Using correct notation, describe an infinite limit.2.2.5 Explain the relationship between one-sided and two-sided limits.2.2.4 Define one-sided limits and provide examples.2.2.3 Use a graph to estimate the limit of a function or to identify when the limit does not exist.2.2.2 Use a table of values to estimate the limit of a function or to identify when the limit does not exist.2.2.1 Using correct notation, describe the limit of a function.In formulas, a limit of a function is usually written as The concept of a limit of a sequence is further generalized to the concept of a limit of a topological net, and is closely related to limit and direct limit in category theory. Limits are essential to calculus and mathematical analysis, and are used to define continuity, derivatives, and integrals. In mathematics, a limit is the value that a function (or sequence) approaches as the input (or index) approaches some value. For more specific cases, see Limit of a sequence and Limit of a function. This article is about the general concept of limit. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |