\magnification = \magstep1

$$
\vec{F} \quad = \quad - {{G M m} \over {r^2}} \ \hat{r}
$$

$$
\rho(r) \quad = \quad \rho_0 {\left( 1 + {{r^2}\over{b^2}} \right) }^{-5/2}
$$

$$
\vec{F} \quad = \quad - {{G \thinspace M_{\rm int} \thinspace m} \over {r^2}} \ \hat{r}
$$

$$
\nabla^2 \Phi \quad = \quad 4 \pi G \rho
$$

$$
{{\rm 100,000\  parsecs}\over{1000}} \quad = \quad {\rm 100\  parsecs}
$$

\bye
