On-line Math 21

1.1  Examples of basic limits

Example 1 Let f(x) = 3x²+1 . Then

lim x® 2  f(x) = 13.

Solution

You can see this most easily by simply plugging into the expression for f(x) at x = 2 . That ought to be the value of f(2) since f(x) has such a simple expression, and that is the case. The general situation of why and when you can evaluate some limits just by plugging in are explained in the section on continuity, and on computing limits.

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Copyright (c) 2000 by David L. Johnson.