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Feedback on complex-eigenvalues

Open rstrauss-logyx opened this issue 4 years ago • 2 comments

In reference to version 224734d7be7ff0c4a8adb3a206356ea122112f33 a.k.a. https://textbooks.math.gatech.edu/ila/complex-eigenvalues.html The 3x3 example is wrong. The eigenvalues are correct, but the last 2 "We can verify" statements is wrong. The product of the first 2 is the middle matrix, but that's not the right product. This is easily seen in the 3rd (bottom) term. Maybe you just matched the eigenvalue 2 with eigenvector 3... At the same time, MatLab gives eigenvector 2 as -0.3660 - 0.2745i -0.2745 + 0.3660i 0.7625 + 0.0000i Why is MatLab's eigenvector about 1/32 as large? Does this factor matter?

rstrauss-logyx avatar Oct 20 '20 18:10 rstrauss-logyx

As long as the two results (for the second eigenvector) are a scalar multiple of each other, it's alright. There's infinitely many eigenvectors for any given eigenvalue. Their union is the corresponding eigenspace.

kaymachi avatar Nov 14 '20 01:11 kaymachi

Still, the "we can verify" statements are wrong. The first statement should have the 4-3i/5 (not the 4+3i/5) and the second should have the 4+3i/5...

rstrauss-logyx avatar Nov 16 '20 00:11 rstrauss-logyx