## where would I use quadratic forms and how?

Wiki defines :In mathematics, a quadratic form is a homogeneous polynomial of degree two in a number of variables.

Yes,all nice and dandy,I get to then express it in terms of matrices and then I find the eigen values and then find the canonical quadratic form,the usual boring linear algebra exercise.But,where could I practically use these forms?For example,in projective geometry,how would I use these?
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 Recognitions: Science Advisor You're implying that linear algebra is boring and projective geometry is not? I'm curious why. I've always found it the other way around.
 I meant linear algebra is always taught in a boring way.Projective geometry classes begin with the Riemann sphere and transformations and other enticing stuff for imagination.Anyway,why would I need a canonical quadratic form? In practical applications like modelling,how is a canonical quadratic form more useful?(other than the fact it has +1 and -1 as coefficients)