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Web skærmformat. - Aarhus Universitet

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I. Differentiation – 2. Partielle afledede 50<br />

Ligningen<br />

kaldes Laplaces ligning.<br />

Ligningen<br />

kaldes bølgeligningen.<br />

∂ 2 u<br />

∂x2 + ∂2u ∂y<br />

2 = 0<br />

∂2u ∂t2 = a2 ∂2u ∂x2 2.29. Laplaces ligning ☞ [S] 11.3 Partial derivatives<br />

Eksempel 8<br />

Funktionen u(x,y) = e x sin y er løsning til Laplaces ligning<br />

Løsning<br />

giver<br />

uxx + uyy = 0<br />

ux = e x siny, uxx = e x siny<br />

uy = e x cos y, uyy = −e x siny<br />

uxx + uyy = 0<br />

2.30. Bølgeligningen ☞ [S] 11.3 Partial derivatives

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