One-sided limits and existence of a two-sided limit
Consider the function
Consider the function defined above. Investigate the behavior of for near , both from the left and from the right, using the graph below as a guide.
Does exist? If it exists, give its value; if it does not exist, explain which of the standard reasons applies.
Hint
Compute or estimate the left-hand limit and the right-hand limit separately using the definition of on each side. Remember that the value is irrelevant to the limit.
Step-by-step solution
For , we have , so , giving . Thus for all near from the left, so .
For , we have , so , giving . Thus for all near from the right, so .
Since the left-hand limit () and the right-hand limit () are not equal, the two-sided limit does not exist. Note that the value plays no role in this conclusion, since limits depend only on behavior near , not at .
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