We consider a generalized equation governed by a strongly monotone and
Lipschitz single-valued mapping and a maximally monotone set-valued mapping in
a Hilbert space. We are interested in the sensitivity of solutions w.r.t.
perturbations of both mappings. We demonstrate that the directional
differentiability of the solution map can be verified by using the directional
differentiability of the single-valued operator and of the resolvent of the
set-valued mapping. The result is applied to quasi-generalized equations in
which we have an additional dependence of the solution within the set-valued
part of the equation.