Despite convention, it is reasonable to consider sqrt(3) to have ambiguous sign since inverse(square) is a multi-valued function (as is arctan). So you can have

Despite convention, it is reasonable to consider sqrt(3) to have ambiguous sign since inverse(square) is a multi-valued function (as is arctan). So you can have arctan(-sqrt(3)) = arctan(sqrt(3)) = pi/3 (allowing for arbitrary selection from multi-valued functions) This is a problem in general with the design of calculators and single-result algorithms in general. The -1 might be needed to trigger the bug. The Citizen calculator has a reputation for bad math: https://forum.kerbalspaceprogram.com/index.php?/topic/119681-stupid-calculators/ https://forum.kerbalspaceprogram.com/index.php?/topic/119681...