  In six chosen scenarios for the $q^2$ dependence of the form factors involved
in $D_s^+ \rightarrow \phi $ transition, we have determined the allowed domain
of $x = A_2(0) / A_1(0)$ and $y = V(0)/A_1(0)$ from the experimentally measured
ratios $R_{sl} = \Gamma(D_s^+ \rightarrow \phi l^+ \nu_l)/\Gamma(D_s^+
\rightarrow \phi \pi^+)$ and $R_h = \Gamma(D_s^+ \rightarrow \phi
\rho^+)/\Gamma(D_s^+ \rightarrow \phi \pi^+)$ in a scheme that uses the $N_c
=3$ value of the phenomenological parameter $a_1$ and includes nonfactorized
contribution. We find that the experimentally measured values of $x$ and $y$
from semileptonic decays of $D_s^+$ favor solutions which have significant
nonfactorized contribution, and, in particular, $R_{sl}$ favors solutions in
scenarios where $A_1(q^2)$ is either flat or decreasing with $q^2$.
