Calculate cost of capital and firm value and decide the optimal debt ratio using the following information.

$\backslash$table$[[$Unlevered beta,$1\mathrm{.}00],[$Tax rate,$0\mathrm{.}20],[$Risk free rate,$0,06],[$Expected mareket return,$-0\mathrm{.}12],[$FCCF$/$EBIT$,40,000]]$

$\backslash$table$[[$D$/$A$,$D$/$E$,\backslash$table$[[$Leveraged$],[$Beta$,$ BL$]],kd,\backslash$table$[[$Kd$],[(1-t)$