Timeline for How do I get the square root of a complex number?
Current License: CC BY-SA 4.0
32 events
| when toggle format | what | by | license | comment | |
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| Jan 7, 2020 at 22:14 | comment | added | AD - Stop Putin - | I would say one must be careful, the first formula collapses at $z=-1$. | |
| Sep 20, 2019 at 1:12 | comment | added | ben | Awesome answer! An extra thought on the geometric construction: If z is located within the unit circle, seems you can use a similar construction method, but would need to swap the roles of the circles to get an intersection. Using the the intersection of the tangent to circle around the origin radius |z| (instead of 1) with the circle around 1/2 through 1 (instead of around z/2 through z). | |
| Jun 21, 2019 at 14:19 | history | edited | J. W. Tanner | CC BY-SA 4.0 | corrected comma splices |
| May 3, 2018 at 14:11 | comment | added | Hans Lundmark | @NickBoshaft: I rolled back your edit. The issue is with $z$ on the negative real axis, and for those $z$ the formula really breaks down. Your comment along with the edit seemed to indicate that you were thinking of $z$ in the left half plane (but not on the negative real axis), and for those $z$ there is indeed no problem (but also no need for a separate drawing). | |
| S May 3, 2018 at 14:05 | history | rollback | Hans Lundmark | Rollback to Revision 8 - Edit approval overridden by post owner or moderator | |
| May 2, 2018 at 19:08 | history | suggested | Nick Boshaft | CC BY-SA 4.0 | Edited to cover the case of real(z)<0. |
| May 2, 2018 at 17:59 | review | Suggested edits | |||
| S May 3, 2018 at 14:05 | |||||
| Apr 16, 2018 at 20:15 | comment | added | David Robertson | As the pictures show, this formula bisects the argument of z and rescales to have the appropriate modulus. Does the fact that we can't trisect angles with a compass and ruler suggest that there's no analogous formula for $\sqrt[3]{z}$? | |
| Jul 2, 2016 at 9:45 | comment | added | Nabin | Wow. Just wow. Loved the first simple answer. :-) Thank you so much | |
| Jan 6, 2014 at 14:55 | comment | added | legends2k | @Did Thanks for clearing that up, I was getting confused for sometime looking at it. | |
| Jan 6, 2014 at 14:54 | history | edited | Did | CC BY-SA 3.0 | deleted 34 characters in body |
| Jan 6, 2014 at 14:53 | comment | added | Did | @legends2k Right, the formula gets even simpler... Thanks for noticing this. Since you checked the formula, I cancelled the mention "unless I am mistaken". | |
| May 26, 2013 at 7:38 | history | edited | Did | CC BY-SA 3.0 | deleted 5 characters in body |
| Jun 11, 2011 at 14:49 | comment | added | t.b. | @Hans: very true. To reduce confusion, I deleted my comment :) | |
| Jun 11, 2011 at 14:47 | history | edited | t.b. | CC BY-SA 3.0 | added 327 characters in body; added 160 characters in body |
| Jun 10, 2011 at 17:40 | comment | added | Hans Lundmark | @Theo: This conversation is not going to make much sense to anyone else after we both edited our comments almost at the same time... ;) | |
| Jun 10, 2011 at 12:45 | comment | added | Did | Hans, @Theo: Deleted my answer. Thanks to both of you. | |
| Jun 10, 2011 at 12:34 | comment | added | Hans Lundmark | I've made the answer CW. | |
| Jun 10, 2011 at 12:32 | history | made wiki | Post Made Community Wiki by Hans Lundmark | ||
| Jun 10, 2011 at 12:29 | comment | added | t.b. | @Hans: Thanks! Glad you like them. | |
| Jun 10, 2011 at 12:26 | comment | added | Hans Lundmark | @Theo: Nice pictures! :) | |
| Jun 10, 2011 at 12:26 | comment | added | Hans Lundmark | @Didier: That's fine with me. As far as rep is concerned, I don't care either. We could make this answer CW. | |
| Jun 10, 2011 at 12:25 | comment | added | t.b. | Hans, @Didier: I added a little bit to the aggression since I think the people at GeoGebra deserve being mentioned prominently for creating such a nice and free tool. | |
| Jun 10, 2011 at 12:23 | history | edited | t.b. | CC BY-SA 3.0 | added 75 characters in body |
| Jun 10, 2011 at 12:19 | history | edited | Did | CC BY-SA 3.0 | added 51 characters in body |
| Jun 10, 2011 at 12:17 | comment | added | Did | Hans, @Theo: Done (at the risk of being seen as aggressive...). As soon as Hans says he is OK with the expanded version of his post, I will delete mine. | |
| Jun 10, 2011 at 12:12 | history | edited | Did | CC BY-SA 3.0 | added 1065 characters in body |
| Jun 10, 2011 at 11:53 | comment | added | t.b. | Since you can't see it on my deleted post, here's @Didier's original comment: "Theo and @Hans: What do you think about the idea of making one single post from our three complementary answers? (Re reputation, if that matters, either one of you may sign the resulting post, I really do not care.)" I refrain from adding Didier's answer in since it seems a bit too aggressive an edit to me, but I'd be strongly in favor of doing it. | |
| Jun 10, 2011 at 11:44 | comment | added | t.b. | Hans: Following a suggestion of @Didier I added two pictures I originally posted as a separate answer. It seemed more reasonable to have them in one answer. I hope you don't mind. | |
| Jun 10, 2011 at 11:42 | history | edited | t.b. | CC BY-SA 3.0 | added two pictures. |
| Jun 10, 2011 at 6:14 | comment | added | Did | @Hans: Yes. This is a question where a picture would be useful (if only I knew how to draw pictures on MSE (and if I had more time on my hands)). Thanks. | |
| Jun 10, 2011 at 6:10 | history | answered | Hans Lundmark | CC BY-SA 3.0 |