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Exercise 766Calculus › Differential equations › Linear systemsL2Added 2 Nov 2026

A system with three distinct eigenvalues

#eigenvalues#eigenvectors#general solution

Statement

Solve X′=AXX' = AX where
A=(011−121101).A = \begin{pmatrix} 0 & 1 & 1 \\ -1 & 2 & 1 \\ 1 & 0 & 1 \end{pmatrix}.

Hint

The characteristic polynomial is X(X−1)(X−2)X(X-1)(X-2). Find the eigenvectors.

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Solution

Eigenvalues. 0,1,20, 1, 2.

Eigenvectors.
- For λ=0\lambda=0: u0=(1,1,−1)u_0 = (1,1,-1).
- For λ=1\lambda=1: u1=(0,−1,1)u_1 = (0,-1,1).
- For λ=2\lambda=2: u2=(1,1,1)u_2 = (1,1,1).

General solution.
X(t)=λu0+μetu1+γe2tu2.X(t) = \lambda u_0 + \mu e^t u_1 + \gamma e^{2t} u_2.