![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbjrWXDCihS9nEGiqd42pXBeAFZ9061832_TacTxhH8SZWyM1ujxpS8nxzs2MKnF2kUy_gUtEddophx24myDkCxMCsbZS_AT1xuzJy4weBXmVDVjxr0OEw1Y-RzWeKHcUMbikrcdVXn-oN/s400/mat2.jpg)
Can you find me a 2x2 matrix, such that when it's multiplied by itself, yields:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMaUlRMdoVcGv2SfRxZP-tqzUId5o5UsqbTerz8SxZR1Zj_bu6G1NJpr3ceUy4vUHUGK9puZJZmaSTeLBWnfcsz_eOzUBBZi4cJaKwR7hxcqyHcdNGBnk85k6dQi9HXJcLNm0Q1IE561gn/s400/mat1.jpg)
There's about 10000000000000000000000000000000000 such matrices by the way. So if you can find 1, and you think you're smart, think again. Haha.
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Well, even though this post has been here for the longest time, it seems that no one has ventured beyond perfunctory reading, so I guess I'll just carry on.
One possible matrix would be:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiddRv7uiRU6L27TuHENBu4SB-GOFj43N2OBC8t0M9x_4-FfSiVFHWuIJ6WCrp_D9ii7HHfHsyy-xZ0WZQyS12QL6QsZhjoJk3M1-R8uGASuMWUjSvAiS_NO9B4Z-AUVjAQZ3kbPpdg1VYA/s400/gg.jpg)
And another would be:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx1TA8hTRkOWQ-hWUbz3AvCdcdVgMoyn8LQTBr8umMnEJsbxa4KWhx-LhWq0P_5Z4p3WwKuEDahzJU03HKlbkwQwS8-tcrHQ2QahW0WGJjwDNt0plKSGMYAGiJ7pBqy1bcySqdoFEuplyi/s400/aa.jpg)
There's actually a pattern: the number in the upper left and lower right positions are the same! But of course, you'd need the right combination. Heh. Can you find any more? There's probably a million more of these, haha.
1 comment:
If you're allowing all real entries, I think there are uncountably many...?
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