Each optimization problem must have certain parameters called

When the optimization problem cost functions are differentiable, the problem is referred to as

The feasible region for the inequality constraints with respect to equality constraints

The degrees of freedom for an optimization problem that has four design variables is

All design optimization problems have only linear inequality constraints. 

The design optimization problem is infeasible when it meets all requirements.

All design variables should be independent of each other.

A feasible design may violate equality constraints. 

The inputs of engineering models include design variables and material properties.

The feasible region for an equality constraint is a subset of that for the same constraint expressed as an inequality.