Quickly converging series for cos

[Deadstar]

Hey folks just wondering whether anyone here knew of a series for cos(x) that converges fairly quickly for values between 0 and 2*pi? The 'usual' series takes up to around the 10th term before it starts looking decent for cos(2*pi) for example.

[mathman]

Why do you need it for that range? If you use it from 0 to π/2, you can easily get it for the rest of the interval.

[TylerH]

Simpson's method is pretty good. You could also try Taylor expansion.

mathman has a good suggestion. The smaller the range the easier it is to get better accuracy throughout.