Checking the three-part continuity test at x = 0
Consider the piecewise function You may use the known fact that .
Using the three-part definition of continuity, determine whether is continuous at . Explicitly state the value of , the value of , and whether these two values are equal. Based on this, is continuous at , and if not, which of the three continuity conditions fails and what type of discontinuity (removable, jump, or infinite) occurs there?
Hint
Evaluate directly from the definition, then use the given fact to find the limit. Compare the two numbers to check the third condition of continuity.
Step-by-step solution
First check condition 1: is defined? By the definition of the piecewise function, , so this condition is satisfied. Next check condition 2: does exist? Since for all near , and we are given that , the limit exists and equals .
Finally check condition 3: does ? We found but , so these values are not equal. Therefore condition 3 fails, and is not continuous at . Since the limit exists but does not match the function value, this is a removable discontinuity — the graph has a hole at that could be patched by redefining .
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