NDEigenvalues

NDEigenvalues[ℒ[u[x, y, ...]], u, {x, y, ...} ∈ Ω, n] gives the n smallest magnitude eigenvalues for the linear differential operator ℒ over the region Ω.

• NDEigenvalues[{ℒ1[u, v, ...], ℒ2[u, v, ...], ...}, {u, v, ...}, {x, y, ...} ∈ Ω, n] gives eigenvalues for the coupled differential operators over the region Ω.
• NDEigenvalues[eqns, {u, ...}, t, {x, y, ...} ∈ Ω, n] gives the eigenvalues in the spatial variables for solutions of the coupled time-dependent differential equations eqns.

Examples

NDEigenvalues[{-Laplacian[u[x, y], {x, y}], DirichletCondition[u[x, y] == 0, True]}, 
  u, {x, y} \[Element] Disk[], 5]

NDEigenvalues[-u''[x], u, {x, 0, Pi}, 3]

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