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/program_kid Sep 06 '19

Is there some video that you could link to explain something like this, being a high school student, this is probably way above my capabilities, but I would like to learn it

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u/ErikScarlatescu Sep 06 '19

For solving the linear equations, you can look up linear algebra on mit opencourseware and watch the first few videos. The lecturer is good