PSet 7.2 (6)

[Kenji Hiranabe]

From:	Hiranabe, Kenji [e-mail]
To:	Gil Strang [e-mail]
日付:	2023/09/07 11:44
件名:	Problem 7.2(Introduction, everyone)
送信元:	esm.co.jp

Prof. Strang,

Hello, again, I have one question.

Attached, here's Problem 6 in Pset7.2 in the "Introduction 6" and
"everyone"(the same section number, and the problem number), and its
answer in the solution manual.

I highlighted by a red circle. Why F3(x, y)=x^2+y^2 is positive semidefinite
(in the sense of linear algebra definition) ?
There was a mention in the "everyone" solution, but just "So" is there.
and I'm not convinced. There was no mention in the "introduction" solution.

And also the problem asks for the singular values and vectors, but no
mention in "introduction". "everyone" mentions a rough estimation and
a suggestion to the computational solution.

Thank you, Professor Strang, I'm always so happy to learn new things in LA.
So beautiful. (LA is linear algebra, not Los Angeles)

Best,
-Kenji

[Kenji Hiranabe]

This should be in linearalgebra repo.