How do calculators calculate trig function?

[Superposed_Cat]

Hi I was wondering how calculators calculate trigonometric functions. Do they use taylor polynomials(if so what order) or what? any help appreciated.

 

[SteamKing]

They use a method called CORDIC, which is much faster than evaluating Taylor polynomials:

http://www.qc.cuny.edu/Academics/Degrees/DMNS/Faculty%20Documents/Sultan1.pdf

 

[D H]

They use a method called CORDIC, which is much faster than evaluating Taylor polynomials.

And range reduction algorithms combined with minimax polynomials are even faster.

A computer is more likely to use range reduction algorithms combined with minimax polynomials, a calculator, CORDIC. Calculators use CORDIC because it reduces chip size. Computers use range reduction and minimpax polynomials because they are fast and accurate. *Nobody* in their right mind uses Taylor series.

 

[Superposed_Cat]

could you send me a link DH? I did google it but nothing I could see off a cursory look.

 

[AlephZero]

This is the classic reference.
https://www.amazon.com/dp/0138220646/?tag=pfamazon01-20

 

[D H]

http://books.google.com/books/about/Computer_approximations.html?id=7vVQAAAAMAAJ

 

[Superposed_Cat]

Thanks, is there a place that online that i can learn from? i don't want to buy a book on it.

 

[nevere]

you guys are great I always wondered how calculators do calculations, where did you guys learn about these books? was it in school or by word of mouth? do these books reflect your age? 1960's computer scientists? lol