Question

surface area element.

I am trying to remember how to find the surface area element of one of the faces of this pyramid.

Answer 1

so I am looking for \(d\vec{a}\). I know that this plane can be written as \[\frac{x}{a}+\frac{y}{b}+\frac{z}{c}=1\]

Answer 2

so I know how to get a vector normal to this surface. just a little bit unclear what how to turn that into "\(d\vec{a}\)"

Answer 3

surface area element can be calculated ( lets call you surface f)

|(div f)|dxdy / |[(div f) dot (z direction)]|
if you want it as a vector you multiply it by the normal.