http://i34.tinypic.com/wu5k414.png

I don't understand how to prove this considering f(x) is not specifically given....(Wondering)

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- October 25th 2009, 09:51 PMJohnLeeeDifferentiability Question
http://i34.tinypic.com/wu5k414.png

I don't understand how to prove this considering f(x) is not specifically given....(Wondering) - October 25th 2009, 10:13 PMredsoxfan325
- October 25th 2009, 10:16 PMJose27
Remember that for a function to be diff. at there exists a linear transformation such that as . Take then and since we have that this goes to as goes to . This proves that is diff. at and . When we can only bound by , but I can't think of a counter-example at the moment for this case.

- October 25th 2009, 10:19 PMredsoxfan325
A good counterexample is with .

- October 25th 2009, 10:27 PMJose27
- October 25th 2009, 10:31 PMredsoxfan325
Oh, in that case how about ?