Newtons method error approximation

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Homework Statement


I've attached the question

Homework Equations


x(n+1) = x(n) - f(x(n)) / f '(x(n))

The Attempt at a Solution



okay so x2= 1.3517323300 and I've already calculated x3 to be 1.3483949227

then how do i estimate the error in x2? do i subtract or something?
 

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I assume they want a percent error as an answer. To do that you do \displaystyle\left|\frac{\text{true value} - \text{estimated value}}{\text{true value}}\right| \times 100

So while your third iteration isn't the "true" value (it's still an approximation), it's more accurate than your second iteration so that's why you would divide by it.
 
nah its not a percent error. Its says |error in x2| =< ...

so if i didn't multiply by 100 it would give me decimal answer.
so it would be | (1.3483949227 - 1.351732330) / 1.3483949227 | yeah??
 
and that equals 0.002475.
 
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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