CSCI 8945 · In-class tool

Eigenvalues & eigenvectors of a 2×2 matrix

Adjust the matrix M and rotate the input vector v with the sliders. The red and orange lines mark the eigenvector directions — the only two orientations where the transformed vector Mv stays parallel to v, just scaled by an eigenvalue.

Matrix M

2.0
1.0
1.0
2.0
M =
2.01.0 1.02.0
trace = 4.00
det  = 3.00

Input vector v

30°
2.0

Transformation view

v = input  ·  Mv = output  ·  eigenvector lines (dashed)

Eigendecomposition

Mv = λv  ⇒  v is an eigenvector with eigenvalue λ.

Eigenvalues & eigenvectors
Current vectors
v =
Mv =
|Mv| / |v| =    angle(v, Mv) =
Drag the θ slider to rotate v. When v aligns with an eigenvector line, Mv becomes parallel to v.