  We present an analysis of the current methods of approximate determination of
the gluon density $G(x,Q^2)$ at low-$x$ from the scaling violations of the
proton structure function $F_2(x,Q^2)$. The gluon density is obtained from
DGLAP equation by expansion at distinct points of expansion. We show that the
different results given by the proposed methods can be obtained from one new
expression considering the adequate points of expansion. It is shown in which
case the approximate determination of $G(x,Q^2)$ is reasonable.
