FunctionSurjective

FunctionSurjective[f,x] tests whether f(x)y has at least one solution x∈ for each y∈Reals.

FunctionSurjective[f,x,dom] tests whether f(x)y has at least one solution x∈dom for each y∈dom.

FunctionSurjective[{f1,f2,…},{x1,x2,…},dom] tests whether f1(x1,x2,…)y1,f2(x1,x2,…)y2,… has at least one solution x1,x2,…∈dom for each y1,y2,…∈dom.

FunctionSurjective[{funs,xcons,ycons},xvars,yvars,dom] tests whether funs(xvars)yvars has at least one solution with xvars∈dom restricted by the constraints xcons for each yvars∈dom restricted by the constraints ycons. 

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