I get 0 with Julia 1.1.1 on Ubuntu: julia> e(x) = x == 0 ? 1 : (exp(x) - 1) / x e (generic function with 1 method) julia> q(x) = abs(x - sqrt(x^2 + 1))

I get 0 with Julia 1.1.1 on Ubuntu: julia> e(x) = x == 0 ? 1 : (exp(x) - 1) / x e (generic function with 1 method) julia> q(x) = abs(x - sqrt(x^2 + 1)) - 1 / (x + sqrt(x^2 + 1)) q (generic function with 1 method) julia> h(x) = e(q(x) ^ 2) h (generic function with 1 method) julia> for x in (15., 16., 17., 9999.) println(h(x)) end 0.0 0.0 0.0 0.0 I get the same in Python. They're all using standard hardware 64 bit floating point numbers in the same way.