We demonstrate a method
to solve Dirichlet problems for semilinear elliptic equations on certain domains by
a combination of change of variables, variational method and super-sub-
solutions method. We show that Dirichlet problems for a semilinear elliptic
equation have a least one solution as long as a relationship between the
growth rate of the nonlinear term and the size of the domain is satisfied.
The result can be applied to semilinear elliptic equations with super-critical
growth.