julia> f2(x)=x[1]*x[2]/(1-x[1]) f2 (generic function with 1 method) julia> a=[0;x[1]] ERROR: UndefVarError: x not defined Stacktrace: [1] top-level scope at none:0 julia> b=[1;1]
Perform a change of variables to a rectangular domain, as explained here and here and here.