# How does this result come about?

• Aug 10th 2012, 10:54 PM
Idiotinabox
How does this result come about?
P(a)−P(b) = a^n(a^n-b^n)+a^n - 1(a^n-1−b^n−1)+...+a^1(a−b) = (a−b)x
How does the RHS come about? I'm not quite sure. I'm looking at a line of proof and can't quite make the connection.
this is given that P(a)=b P(b)=c P(c)=a.
• Aug 10th 2012, 10:56 PM
Prove It
Re: How does this result come about?
Quote:

Originally Posted by Idiotinabox
P(a)−P(b) = a^n(a^n-b^n)+a^n - 1(a^n-1−b^n−1)+...+a^1(a−b) = (a−b)x
How does the RHS come about? I'm not quite sure. I'm looking at a line of proof and can't quite make the connection.
this is given that P(a)=b P(b)=c P(c)=a.

I don't see how it possibly could, because the RHS has an x term and the other side does not.

Why not post the full proof so that we understand the context of the question?
• Aug 10th 2012, 11:05 PM
Idiotinabox
Re: How does this result come about?
http://www.math.ucsb.edu/mathclub/Pr...6Prob3FSol.pdf is the solution. Second line of proof. Sorry, forgot to include that x belongs to set of integer numbers