@testset "5 Inverse trig functions" begin
    include("5.1 Inverse sine/.jl")
    include("5.2 Inverse cosine/.jl")
    include("5.3 Inverse tangent/.jl")
    include("5.4 Inverse cotangent/.jl")
    include("5.5 Inverse secant/.jl")
    include("5.6 Inverse cosecant/.jl")
end
