Fulton, Algebraic curves 4.8

Let $V=mathbb{P}^1$, with corresponding coordinate ring $Gamma_h(V)=k(X,Y)$. Let $t=X/Yin k(V)$. The question is following : Show $k(V)=k(t)$. There is a 1-1 correspondence between points of $mathbb{P}^1$ and the DVR’s with…