#What does it mean to evaluate a double integral over a surface

13 messages · Page 1 of 1 (latest)

uneven lagoon
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In this example, what does the integrand signify? I thought the purpose of a surface integral would be to find the area of S, but then what is the 6xy for? Geometrically, what would it mean if it was lets say x + z instead of 6xy?

cerulean elkBOT
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What does it mean to evaluate a double integral over a surface

short ore
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this integral would indeed yield the area of the surface if we were integrating just 1 instead of 6xy. In every other case it would require a four-dimensional space to visualize it

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you may try to imagine 6xy going up and down in some mystery dimension as it takes on different values of S

uneven lagoon
short ore
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engineer/physicist moment

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it is hard for me to imagine a real world use for this but luckily that's not what math is for

uneven lagoon
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oh

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i'm assuming this is just a pedagogical tool for when you're gonna be calculating the flux through a surface

short ore
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who knows, maybe there is a use for this stuff in relativity or something since we live in 3 + 1 dimensions

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that's what i'd guess if you're studying engineering or physics

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i may've actually been speaking out of my arse here since S is two-dimensional so you do have an extra dimension for visualization