Calculus Volume 1

138

Chapter 2 | Limits

Figure 2.13 The graph of f ( x ) = (sin x )/ x confirms the estimate from Table 2.2 .

Example 2.5 Evaluating a Limit Using a Table of Functional Values 2

x −2

Evaluate lim x →4

using a table of functional values.

x −4

Solution As before, we use a table—in this case, Table 2.3 —to list the values of the function for the given values of x .

x −2

x −2

x

x

x −4

x −4

3.9

0.251582341869

4.1

0.248456731317

3.99

0.25015644562

4.01

0.24984394501

3.999

0.250015627

4.001

0.249984377

3.9999

0.250001563

4.0001

0.249998438

3.99999 0.25000016

4.00001 0.24999984

Table 2.3 Table of Functional Values for lim x →4

x −2

x −4

After inspecting this table, we see that the functional values less than 4 appear to be decreasing toward 0.25 whereas the functional values greater than 4 appear to be increasing toward 0.25. We conclude that

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