Estimating a limit numerically near a hole in the domain
Consider the function . Note that is not defined at , since this gives . We want to understand how behaves for values of near 9, even though it is undefined at 9.
Use a calculator or spreadsheet to evaluate at values of close to on both sides, such as and . Organize your results in a table (you do not need to submit the table itself). Based on the trend you observe as gets closer and closer to from both sides, what is ?
Hint
Notice that is undefined at itself, but you are asked about its behavior for values approaching 9, not at 9. Watch what value the outputs seem to settle toward as gets closer to 9 from each side.
Step-by-step solution
As approaches from the left (e.g., ), computing gives values that get closer and closer to , i.e. approximately . Similarly, approaching from the right (e.g., ) also produces values approaching about . Since the function is undefined exactly at , we rely entirely on this trend from nearby values rather than trying to plug in directly.
Because both the left-hand and right-hand trends converge to the same numerical value, approximately , we conclude that the two-sided limit exists and equals this common value. This matches the algebraic value (obtainable by rationalizing , though that technique isn't required here), confirming .
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