Exercise 7.A.12

Answers

Proof. Let u and w denote normalized eigenvectors corresponding to 3 and 4. By 7.22, u and w are orthogonal. From the Pythagorean Theorem, we have

||u + w||2 = ||u||2 + ||w||2 = 2

and

||T(u + w)||2 = ||3u + 4w||2 = ||3u||2 + ||4w||2 = 9 + 16 = 25.

Letting v = u + w and taking the square root of each equation gives the desired result. □

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2017-10-06 00:00
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