# Tag Info

$y_t$ is independent from $x_{1,t}$ and $x_{2,t}$ by definition, otherwise $u_t$ should be deterministic. It means that $\frac{dx_{1,t}}{dy_t}=0$ and $\frac{dx_{2,t}}{dy_t}=0$. All betas are constant so $\frac{du_t}{dy_t}=1$.