<![CDATA[Complex vs. real results of log(b,a)]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba
Thu, 14 Jan 2021 10:38:52 +0000Wed, 13 Jan 2021 09:10:43 +0000Zend_Feed<![CDATA[If you make a complex number eg z_1 = 1+2 ί then you can use ln(z_1) Complex numbers aren't supported for the other "log" functions in the Algebra View]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba#comment-295872
Wed, 13 Jan 2021 09:52:18 +0000<![CDATA[Hmm, sorry, but this doesn't really answer my question. It's not about complex numbers as an argument for the log-function, but as a result of log(2, -8). GGB Classic yields "undefined" as result, while GGB CAS yields a complex number as result. I wonder, if there is an option to toggle this behaviour (e.g. complex results on/off)?]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba#comment-295882
Wed, 13 Jan 2021 11:33:17 +0000<![CDATA[What follows is not really an answer to your question, but maybe it can be a starting point for developing an application that guides students towards what you would like to achieve. If you type ln(-8), geogebra classic gives you "undefined" If you type ln(-8+0*i), the result is 2.08+3.14i With some user interface this difference in behaviour may be used as some kind of switch.]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba#comment-295896
Wed, 13 Jan 2021 13:57:21 +0000<![CDATA[Ah ok! This behaviour of GGB Classic would be perfectly fine: If my argument is a complex number, the result will also be a complex number. But if my argument is a real number and negative, the result would be undefined. Would it be possible to implement this behaviour in GGB CAS, too? This would also increase the consistency of Classic and CAS. By the way: The graphing calculator behaves as GGB Classic.]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba#comment-295910
Wed, 13 Jan 2021 14:50:12 +0000<![CDATA[Sorry, we won't be changing that]]>
https://help.geogebra.org/topic/complex-vs-real-results-auf-logba#comment-295968
Thu, 14 Jan 2021 10:38:52 +0000