Expressing difference product using Vandermonde determinant.

Adgorn
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Homework Statement


Show that ##g=g(x_1,x_2,...,x_n)=(-1)^{n}V_{n-1}(x)## where ##g(x_i)=\prod_{i<j} (x_i-x_j)##, ##x=x_n## and ##V_{n-1}## is the Vandermonde determinant defined by
##V_{n-1}(x)=\begin{vmatrix}
1 & 1 & ... & 1 & 1 \\
x_1 & x_2 & ... & x_{n-1} & x_n \\
{x_1}^2 & {x_2}^2 & ... & {x_{n-1}}^2 & {x_n}^2 \\
... & ... & ... & ... & ... \\
{x_1}^{n-1} & {x_2}^{n-1} & ... & {x_{n-1}}^{n-1} & {x_n}^{n-1}

\end{vmatrix}##

Homework Equations


N\A

The Attempt at a Solution


After expressing the determinant using the sigma notation I attempted to take a common factor to express it in a similar fashion but to no success. Other than that I really don't know how to approach this (I know I shouldn't say this but it is the case) as I never encountered a proof of this kind, and so I would appreciate some help.
 
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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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