Math Is Fun Forum

I've tidied up the Latex to eliminate an error.  Hope this is what you intended, Bob

Let n be a whole number,n>=2.Real numbers

with the sum s have the property that

Prove that

.
I have been trying to prove it for days but I had no luck.Please help me !
EDIT:Thanks,Bob!It was the first time I have ever tried to write sums in Latex

Hello! I have recently found a problem and I don't know what this notation means.The problem says : find all the triples (x,y,z) for which
{(x-y)/(y-z),(y-z)/(z-x),(z-x)/(x-y)}={x,y,z}.I don't understand what {x,y,z} means.Thanks in advance!