We know from the foregoing that the denominator of the cone reflectance has
at least one root at
. We now investigate the ``dc behavior''
more thoroughly.
We already discovered a root at
and once again the limit is an indeterminate
Thus, two poles and zeros cancel at dc, and the dc reflectance is
Both series begin with the term
which means both the numerator
and denominator have two roots at
. Hence, again the conclusion
is two pole-zero cancellations at dc.
which approaches