It's also commonly used in astronomy to measure the distance on the sky between two objects: https://en.wikipedia.org/wiki/Haversine_formula https://en.wikipedi

It's also commonly used in astronomy to measure the distance on the sky between two objects: https://en.wikipedia.org/wiki/Haversine_formula https://en.wikipedia.org/wiki/Haversine_formula I could imagine these could be useful to be defined by computer libraries, as (see article) it would help reduce large reductions in accuracy for some calculations (e.g. by subtracting similar numbers, or wanting to calculate sin^2).