Help with Real analysis proof about limit laws and functions

kbrono
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Homework Statement


Let f be a function let p /in R. Assume limx->p=L and L>0. Prove f(x)>L/2


The Attempt at a Solution



Let f be a function let p /in R. Given that limx->pf(x)=L and L>0. Since L\neq0 Let \epsilon= |L|/2. Then given any \delta>0 and let p=0 we have |f(x)-L| = |0-L| = |L| > |L|/2=\epsilon. Thus f(x) > |L|/2 near p.
 
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Yes, this seems to be correct!
 
Thank you!
 
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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