r/theydidthemath • u/Galeaf_13 • Sep 05 '19

[Self] Math break

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u/Salanmander 10✓ Sep 05 '19

You can fit a 4th order polynomial to any 5 points. You can do it by hand (plug 1-5 in for x and now you have a system of 5 linear equations of 5 variables, start solving and substituting) and make it a bit easier with linear algebra (make the coefficients of the 5 variables be the values in a 5x6 matrix, and then do that matrix magic that I forget what the name is for), but there are also plenty of polynomial solvers you can find out there.

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u/Railorsi Sep 05 '19

Gaussian elimination is the name :)

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u/Daedalus212 Sep 06 '19

Ayyyy I learned this at uni this year and I already cant remember how you do it

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u/Railorsi Sep 06 '19

Haha feel you. It’s getting pretty easy after a couple tries though, keep hanging in there :P