Question

Find an expression for pn (pn=x^n+y^n) in terms of r1, r2, p_n-1, p_n-2 where r1=(x+y) and r2=(xy). hence explain why every pn can be written in terms of r1 and r2 only.

Answer 1

Worked out how to do the algebra, just the explanation in the second part that I am struggling with.