#determinant of a matrix

13 messages · Page 1 of 1 (latest)

grizzled wolf
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hello, what's the essential role of a determinant for a matrix? my book says it's mainly to find if a matrix is invertible but is that it? surely there's a more important result?
thank you

hot bridgeBOT
cold crown
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The easiest way to interpret the determinant is that it shows how much volumes get scaled

little owl
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It can also be used to solve a system of linear equations and also to check consistency of the system of linear equations. As for geometrical use it can be used to find the areas and volumes of certain shapes . it is also used for finding cross products

cold crown
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If you have a matrix and interpret is as the matrix of a linear operator, then its determinant shows how much the (n-dimensional) volume gets skewed under that operator

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For example, a determinant 0 tells you that you lose at least one dimension and so the n-dimensional volume is lost (imagine projecting a 3d cube onto a plane, its 3d volume becomes 0)

frosty agate
potent tide
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note that to talk about n-volumes we need a measure on the space, but to talk about determinants we don't

sterile hollow
steep idol
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I had to post 3b1b

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He makes great, and often times very intuitive geometric explanations for many abstract math concepts

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Give it a little look