Oh, ok that explains it. Is that why my 16-bit calculator gives me 0? Carsten Haese wrote: > On 14 Oct 2006 20:33:13 -0700, Chris wrote > > >>> from math import * > > >>> sin(0) > > 0.0 > > >>> sin(pi) > > 1.2246063538223773e-016 > > >>> sin(2*pi) > > -2.4492127076447545e-016 > > >>> cos(0) > > 1.0 > > >>> cos(pi) > > -1.0 > > >>> cos(2*pi) > > 1.0 > > > > The cosine function works fine, but I'm getting weird answers for sine. > > Is this a bug? Am I doing something wrong? > > You're apparently not correctly reading python's answer to sin(pi). > 1.2246063538223773e-016 is the scientific notation for the number > 0.00000000000000012246063538223773, which is pretty darn close to zero, the > result you probably expected. > > You're not getting *exactly* zero because you're not passing in *exactly* pi > but a close approximation of pi. > > I'll leave it as an exercise for the reader to explain why cosine seems to > work fine. Hint: Look at cos(pi/2) and sin(pi/2). > > -Carsten
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