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------- Additional comments from [email protected] Wed Apr 15 03:42:30 +0000 2009 ------- The bug persists in OOo 3.0.1/WinXP. It leads to incompatibility with MS Excel and thus, to difficulties in migration. The general math rule says that "For odd values of n, every negative number has a real negative nth root" (http://en.wikipedia.org/wiki/Nth_root). And it's not correct to spaculate that "(-8)^(1/3)=(-8)^(2/6)=((-8)^2))^(1/6)=64^(1/6)=2". This speculation is a sort of sophism that masks the fact that there are more than one nth roots. When you make any transformations of powers you must take into account the possible loss of some roots or introduction of new roots. The correct result of "sqrt(x)" should be a multitude of two (possibly complex) numbers, not a single number. As we cannot return such a result in a spreadsheet we agree to see only positive answer, but it doesn't mean that we don't deserve to get correct negative real number as a cube root of a negative number. To be specific: x != sqrt(x^2), because, strictly speaking, sqrt(x^2) = {x, - x}. So (-8)^(1/3) = (-8)^(2/6) [only if you calculate 2/6 _before_ you calculate the exponent] != ((-8)^2))^(1/6), because here in the last case the base is raised to 2nd power and then the 6th root is taken, and the extra "2" brings new roots here (positive ones). As it can be seen in Issue 24271 (that was erroneously treated as duplicate to this one), the OOo team makes it's best to maintain compatibility with its main competitor. This approach has very strong base and is honored sometimes even if there's a mistake in th MS Office to let users migrate painlessly. But in this case you refuse to make changes that not only consistent with MS Excel, but also mathematically correct! [Workaround] for those who want to find the cube root: SIGN(X)*ABS(X)^(1/3) --------------------------------------------------------------------- Please do not reply to this automatically generated notification from Issue Tracker. Please log onto the website and enter your comments. http://qa.openoffice.org/issue_handling/project_issues.html#notification --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
