Lipschitz Continuity Proof: f(x) = x^(1/3) on (-1,1) Has No Lipschitz Constant

CarmineCortez
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Homework Statement



Show f(x) = x^(1/3) is not lipschitz continuous on (-1,1).

Homework Equations



I have abs(f(x)-f(y)) <= k*abs(x-y)

when I try to show that there is no K to satisfy I have problems
 
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Examine |f'(x)| as x tends to 0.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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