The framework presented results in the two-step method,
which does not directly apply to the general exponentiation
function 
. With appropriate extensions, the two-step method
may generate valid bounds for but it will still
generate bounds which are not optimal.
With the two-step method an upper bound h, of g, was found;
h was then treated as a unary function so that our previous
methods may be applied.
We will remove the intermediate step, and consider g as a
unary function of 
:
The relevant derivatives appear in the table following.
Positive multiplicative factors were removed from some table entries.
Throughout the table 
while 
.
is independent of the sign
of bd, as expected.
The sign of 
reverses as the sign of
bd reverses, as expected.
With either the one-step or two-step method,
efficiency may be improved by considering
the 
regions 
overlap, as was done
in section 
.
| Jeff Tupper | March 1996 |