Using a power series to estimate a function

lindsaygilber
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I'm having a problem with estimating a function using a power series... the problem is

Use the power series for f(x)= (5+x)^(1/3) to estimate 5.08^(1/3) correct to four decimal places.


I found all the derivatives of f(x) but I'm not sure how to make it into a power series or what form to use for a cubic root...
 
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I believe if you use a Taylor Series expansion(which I believe is a power series), you should be able to approximate it using this formula:

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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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