# Grunberg-Nissan Equation Proof

syki

## Homework Statement

Prove:

ln(η) = Σ[xi*ln(ηi)]

2. The attempt at a solution

I tried using the relationship:

Σ(xi)=1

and the rules for adding logarithms, but I seem to be totally failing at this. I'm not asking to have it worked out, but any hints on which direction I should go?