
Re: [HM] Bombelli: Cube root of Complex Nos.
Posted:
Feb 14, 2001 5:57 PM


On Wed, 14 Feb 2001, Bonnie Shulman wrote:
> BUT, in actually computing > the real and imaginary parts of 2 + 11i, I am left evaluating > cos(arctan 11/2) (or sin of same). Is there a way to compute > this analytically (series?) so as to get exactly 2 or 1, rather > than a numerical approximation? [I suspect so, as my calculator > gives the exact answers.]
Any (handheld) calculator will hardly be able to give the exact answer (even if the display seems to say so), nor will be the usual floatingbased programming languages or spreadsheets (due to the inherent limitations of floating point arithmetic with the usually implemented constant "wordlength"), but using a computer algebra system usually will do.
Best regards,
Jochen Ziegenbalg, Karlsruhe

