\magnification=\magstep3

\input ../macros.tex

\hoffset -0.9cm
\voffset -1.0cm
\noblackbox
\nopagenumbers


$$ 
W\ =\ -\,{G\over2}\ \int_0^{\infty}{M^2(r)\over r^2}\ dr
$$

$$
\rho(r)\ =\ \left({M\over 4\pi r_J^3}\right)\ {r_J^4\over r^2(r+r_J)^2}
$$


$$
\Phi(r)\ =\ {G\,M\over r_J}\ \ln\left({r\over r+r_J}\right)
$$

$$
I(R)\ =\ I(R_e)\, exp\left\{-b\left[(R/R_e)^{1/n} -\, 1\right]\right\}
$$

$$
L\ =\ \int_0^{\infty} I(R)\, 2\pi R\,  dR\ =\ 8!\, {e^{7.67}\over 
(7.67)^8}\,\pi R_e^2\, I(R_e)\ \approx\ 7.22\, \pi R_e^2\, I(R_e)
$$

\bye

