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 P: 70 It was pretty cool to stumble upon Euler's formula as the eigenvalues of the rotation matrix. det(Rot - kI) = (cos t - k)2 + sin2t =k2-2(cos t)k + cos2t + sin2t =k2-2(cos t)k + 1 k = {2cos t +/- $$\sqrt{4cos^2(t) - 4}$$}/2 k = cos t +/- $$\sqrt{cos^2(t) - 1}$$ k = cos t +/- $$\sqrt{cos^2(t) - cos^2t - sin^2(t)}$$ k = cos t +/- $$\sqrt{-sin^2(t)}$$ k = cos t +/- i sin t = e(+/-)it I was wondering what the eigenvalues are for the rotation matrix in 3D, and if there's a 3D equivalent to Euler's formula.