Eigenvector result is unusual

06242014, 12:52 AM
(This post was last modified: 06242014 01:14 AM by Rich.)
Post: #1




Eigenvector result is unusual
Hi,
When i type in EIGENVV([1,2],[4,3]) I get this result: {[[0.4472135955,−0.7453559925],[0.894427191,0.7453559925]],[[5.,0],[0,1.]]} I am not sure if my math is wrong somewhere, but on paper i get the different eigenvalues, for 5, i get [1 2] and for 1, I get [1 1] which is what wolfram alpha gets. My 50G gets a value of [.5 1] and [1 1] for for 5 and 1 respectively. Which is also correct. EDIT::: Actually looking a little past the abstract, the results are correct, but I am not sure why the HP Prime didn't come up with a number closer to a whole number or more readable output similar to the 50G. 

06242014, 01:28 AM
Post: #2




RE: Eigenvector result is unusual
I don't think the math is wrong.
The eigenvalues of lambda1 and lambda2 are correct (5, and 1), and this is also what Wolfram alpha shows. The eigenvectors are [.44..., .89...], and multiplied by a suitable scaling factor equals [1,2], and ditto for the other eigenvector [.74..., .74], which, again, multiplied with a suitable scaling factor equals [1,1]   again in agreement with Wolfram alpha. I believe you read the vectors the wrong way   horizontally instead of vertically. But we can ask   why doesn't the Prime normalize the eigenvectors? 

06242014, 01:39 AM
(This post was last modified: 06242014 01:40 AM by Rich.)
Post: #3




RE: Eigenvector result is unusual
Thanks for the update, I was reading it wrong. I noticed that it when diagonalizing the matrix on the Prime, with those eigenvectors, it still gives me the correct result but instead of a zeros, it has 1.42109E15, which is essentially zero... but maybe due to the original output.


06242014, 05:27 AM
Post: #4




RE: Eigenvector result is unusual
EIGENVV is an approx instruction. Try an exact one, for example jordan.


06242014, 11:41 AM
Post: #5




RE: Eigenvector result is unusual
Thank you, the Jordan function works perfectly.


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