Simplification to Final Form

Here we will work on Equation (58) of the text, the one that will become the equation that determines $\beta (r)$, in order to put it in final form for further analysis. That equation is written as


\begin{displaymath}
r\left[r\nu'(r)\right]'
+
\left[
r\nu'(r)
\right]^{2}
...
...)
\right]
+
\,{\rm e}^{2\lambda(r)}
\omega\mathfrak{T}(r).
\end{displaymath} (124)

We will now work, in turn, on the right-hand and left-hand sides of this equation. Using the results obtained in the text for $\lambda(r)$, $\lambda'(r)$ and $\mathfrak{T}(r)$, we can write the right-hand side as


$\displaystyle {\rm RHS}$ $\textstyle =$ $\displaystyle -\,
\frac{r_{M}}{2}\,
\frac
{\beta(r)-\left[r\beta'(r)\right]}
{r-r_{M}\beta(r)}
+
\frac
{r\omega r_{M}\beta'(r)}
{r-r_{M}\beta(r)}\,$  
  $\textstyle =$ $\displaystyle \frac{r_{M}}{2}\,
\frac
{2\omega\left[r\beta'(r)\right]}
{r-r_{M}...
...
-
\frac{r_{M}}{2}\,
\frac
{\beta(r)-\left[r\beta'(r)\right]}
{r-r_{M}\beta(r)}$  
  $\textstyle =$ $\displaystyle \frac{r_{M}}{2}\,
\frac
{
2\omega\left[r\beta'(r)\right]
-
\beta(r)
+
\left[r\beta'(r)\right]
}
{r-r_{M}\beta(r)}$  
  $\textstyle =$ $\displaystyle \frac{r_{M}}{2[r-r_{M}\beta(r)]}\,
\left\{
\rule{0em}{2.5ex}
(1+2\omega)\left[r\beta'(r)\right]
-
\beta(r)
\right\}.$ (125)

For convenience in the manipulations that follow afterward, we may write the final form of this equation as


$\displaystyle {\rm RHS}$ $\textstyle =$ $\displaystyle \frac{r_{M}}{4[r-r_{M}\beta(r)]^{2}}\,
\left\{
\rule{0em}{2.5ex}
...
...r)\right]
-
2\beta(r)
\right\}
\left[
\rule{0em}{2.5ex}
r-r_{M}\beta(r)
\right]$  
  $\textstyle =$ $\displaystyle \frac{r_{M}}{4[r-r_{M}\beta(r)]^{2}}\,
\left\{
\rule{0em}{2.5ex}
2(1+2\omega)r\left[r\beta'(r)\right]
-
2r\beta(r)
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
-
2(1+2\omega)r_{M}\beta(r)\left[r\beta'(r)\right]
+
2r_{M}\beta^{2}(r)
\rule{0em}{2.5ex}
\right\}.$ (126)

As one can see, this involves the function $\beta (r)$, its derivative $\beta'(r)$, and the parameters $\omega$ and $r_{M}$. Using again the results obtained in the text for the relevant quantities, we can now write the left-hand side of our $\theta$ component equation as


$\displaystyle {\rm LHS}$ $\textstyle =$ $\displaystyle \frac{r_{M}}{2[r-r_{M}\beta(r)]^{2}}
\left(
\rule{0em}{3ex}
\omeg...
...t[
r
-
r_{M}\beta(r)
\right]
\left\{r\left[r\beta'(r)\right]'\right\}
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
+
\omega
r_{M}
\left[r\beta'(r)\right]^{2}
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
+
(1-\omega)
r
\left[r\beta'(r)\right]
-
r
\beta(r)
\rule{0em}{3ex}
\right)
+$  
    $\displaystyle +
\frac{r_{M}^{2}}{4[r-r_{M}\beta(r)]^{2}}
\left\{
\rule{0em}{3ex}
\beta(r)+\omega\left[r\beta'(r)\right]
\right\}^{2}
+$  
    $\displaystyle +
\frac{r_{M}^{2}}{4[r-r_{M}\beta(r)]^{2}}
\left\{
\rule{0em}{3ex...
...right\}
\left\{
\rule{0em}{3ex}
\beta(r)+\omega\left[r\beta'(r)\right]
\right\}$  
  $\textstyle =$ $\displaystyle \frac{r_{M}}{4\left[r-r_{M}\beta(r)\right]^{2}}
\times$  
    $\displaystyle \times
\left(
\rule{0em}{3ex}
2\omega
\left[
r
-
r_{M}\beta(r)
\r...
...\beta'(r)\right]'\right\}
+
2\omega
r_{M}
\left[r\beta'(r)\right]^{2}
+
\right.$  
    $\displaystyle \hspace{2em}
\left.
\rule{0em}{3ex}
+
2(1-\omega)
r
\left[r\beta'(r)\right]
-
2r
\beta(r)
+
r_{M}
\beta^{2}(r)
+
\right.$  
    $\displaystyle \hspace{2em}
\left.
\rule{0em}{3ex}
+
2\omega
r_{M}
\beta(r)
\lef...
...]
+
\omega^{2}
r_{M}
\left[r\beta'(r)\right]^{2}
+
r_{M}
\beta^{2}(r)
+
\right.$  
    $\displaystyle \hspace{2em}
\left.
\rule{0em}{3ex}
+
\omega
r_{M}
\beta(r)\left[...
...'(r)\right]
-
\omega
r_{M}
\left[r\beta'(r)\right]^{2}
\rule{0em}{3ex}
\right).$ (127)

Some simplifications can now be made, so that we may write that


$\displaystyle {\rm LHS}$ $\textstyle =$ $\displaystyle \frac{r_{M}}{4\left[r-r_{M}\beta(r)\right]^{2}}
\left(
\rule{0em}...
...t[
r
-
r_{M}\beta(r)
\right]
\left\{r\left[r\beta'(r)\right]'\right\}
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
\rule{0em}{3ex}
+
\omega(1+\omega)
r_{M}
\left[r\beta'(r)\right]^{2}
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
\rule{0em}{3ex}
+
2(1-\omega)
r
\left[r\beta'(r)\right]
-
2r
\beta(r)
+
\right.$  
    $\displaystyle \hspace{8em}
\left.
+
2r_{M}
\beta^{2}(r)
+
(3\omega-1)
r_{M}
\beta(r)
\left[r\beta'(r)\right]
\rule{0em}{3ex}
\right).$ (128)

Using the expressions for the left-hand and right-hand sides we may now write for the $\theta$ component of the field equation,


$\displaystyle {
\rule{0em}{3ex}
2\omega
\left[
r
-
r_{M}\beta(r)
\right]
\left\...
...ight\}
+
\omega(1+\omega)
r_{M}
\left[r\beta'(r)\right]^{2}
+
}
\hspace{10em}
$
$\displaystyle {
\rule{0em}{2.5ex}
+
2(1-\omega)
r
\left[r\beta'(r)\right]
-
2r
...
...ta^{2}(r)
+
(3\omega-1)
r_{M}
\beta(r)
\left[r\beta'(r)\right]
}
\hspace{9em}
$
  $\textstyle =$ $\displaystyle \rule{0em}{2.5ex}
2(1+2\omega)r\left[r\beta'(r)\right]
-
2r\beta(r)
+$  
    $\displaystyle \rule{0em}{2.5ex}
-
2(1+2\omega)r_{M}\beta(r)\left[r\beta'(r)\right]
+
2r_{M}\beta^{2}(r).$ (129)

Some of the terms now cancel off, and passing all the remaining terms to the left-hand side we are left with


$\displaystyle 2\omega
\left[
r
-
r_{M}\beta(r)
\right]
\left\{r\left[r\beta'(r)\right]'\right\}
+
\omega(1+\omega)
r_{M}
\left[r\beta'(r)\right]^{2}
+$      
$\displaystyle +
(2-2\omega)
r
\left[r\beta'(r)\right]
+
(3\omega-1)
r_{M}
\beta(r)
\left[r\beta'(r)\right]
+$      
$\displaystyle \rule{0em}{3ex}
-
(2+4\omega)
r
\left[r\beta'(r)\right]
+
(2+4\omega)
r_{M}
\beta(r)
\left[r\beta'(r)\right]$ $\textstyle =$ $\displaystyle 0.$ (130)

One can see that some more terms will cancel off. For convenience we will write this equation with an extra overall factor of $r_{M}$, as


$\displaystyle 2\omega
r_{M}
\left[
r
-
r_{M}\beta(r)
\right]
\left\{r\left[r\beta'(r)\right]'\right\}
+
\omega(1+\omega)
r_{M}^{2}
\left[r\beta'(r)\right]^{2}
+$      
$\displaystyle -
6\omega
r
r_{M}
\left[r\beta'(r)\right]
+
(1+7\omega)
r_{M}^{2}
\beta(r)
\left[r\beta'(r)\right]$ $\textstyle =$ $\displaystyle 0,$ (131)

so that it is now ready for the further manipulations made in the text.