Cant understand this transition

  • Thread starter Thread starter nhrock3
  • Start date Start date
  • Tags Tags
    Transition
nhrock3
Messages
403
Reaction score
0
http://i50.tinypic.com/2a6w9qg.jpg

cant see how they put the only the denominator to be equal the new expression.
?
 
Physics news on Phys.org
They used

\frac{1}{1-x}=1+x+x^2+x^3+...

where x=2z^2/4!+.... It looks like they made a sign mistake when they did that, though.
 
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...
Back
Top