Dear users,

I need to minimize this nonlinear function: f(x1,x2) = 1 + x2^2 - x - sin(x1) with box constraints.

How can I do this by using a function, named E-restrito, providing as argument f?

My code is:

```
function E_restrito( f(x1,x2) )
optimizer = Juniper.Optimizer
params = Dict{Symbol,Any}()
params[:nl_solver] = with_optimizer(Ipopt.Optimizer, print_level=0)
modelo = Model(with_optimizer(optimizer, params))
@variable(modelo, l[i] <= x[i in 1:2] <= u[i], start = 1)
@objective(modelo, Min, f(x1,x2))
optimize!(modelo)
end
```