Saturday, 20 September 2014

trigonometry - How is fracsin(x)x=1 at x=0




I have a function:
sinc(x)=sin(x)x


and the example says that: sinc(0)=1, How is it true?




I know that limx0sin(x)x=1, But the graph of the function sinc(x) shows that it's continuous at x=0 and that doesn't make sense.


Answer



In an elementary book, they should define sinc like this
sincx={sinxxx01x=0


and then immediately prove that it is continuous at 0.



In a slightly more advanced book, they will just say
sincx=sinxx


and the reader will understand that removable singularities should be removed.


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